1. A simple machine helps a person in doing :
(a) Less work
(b) The same amount of work with lesser force
(c) The same amount of work slowly
(d) The same amount of work much faster
[I.A.S. (Pre) 1996]
Ans. (b) The same amount of work with lesser force
- Simple machines make it easier to do the same amount of work with less effort.
- Examples of simple machines include pulleys, levers, wheels, and screws.
|
2. A man is standing on a sensitive balance.
(a) Increases
(b) Decreases
(c) Remains unaffected
(d) May increase or decrease depending on the atmospheric pressure
[U.P.P.C.S. (Mains) 2013]
Ans. (a) Increases
- If someone takes a deep breath, it will make the reading on the scale go up.
- One liter (L) of air weighs about 1.225 grams (g).
- If someone takes a deep breath of 4.8L of air, it will add about 5.88g to their weight.
- This will cause their weight to increase slightly.
|
3. Which of the following is not a vector quantity?
(a) Displacement
(b) Velocity
(c) Force
(d) Volume
[45th B.P.S.C. (Pre) 2001]
Ans. (d) Volume
- A scalar quantity is a quantity that has only size, but not direction.
- Vector quantity has both size and direction.
- Displacement, velocity, and force are all vector quantity examples, but volume is a scalar quantity.
|
4. Which of the following is a vector quantity?
(a) Time
(b) Speed
(c) Displacement
(d) Distance
[U.P.R.O./A.R.O. (Mains) 2014]
Ans. (c) Displacement
- A vector quantity has both size and direction.
- Examples of this type of quantity are displacement, velocity, and force.
- Volume is a type of quantity that only has size, not direction.
|
5. Which one of the following is a scalar quantity?
(a) Force
(b) Pressure
(c) Velocity
(d) Acceleration
(e) None of the above/More than one of the above
[65th B.P.S.C. (Pre) 2019]
Ans. (b) Pressure
- Force, velocity, and acceleration are vector quantities, meaning they have directions.
- Pressure is different as it is a scalar quantity.
- Pressure is the amount of force pushing down on an area.
- Force is like a pull or push in a single direction.
|
6. Which one of the following is a vector quantity?
(a) Momentum
(b) Pressure
(c) Energy
(d) Work
[I.A.S. (Pre) 1997]
Ans. (a) Momentum
- Momentum is a type of measurement that has direction, while the other choices are measurements that only have a size.
|
7. Which physical quantity is represented by the ratio of momentum and velocity of the body?
(a) Velocity
(b) Acceleration
(c) Mass
(d) Force
[45th B.P.S.C. (Pre) 2001]
Ans. (c) Mass
- Momentum is a type of quantity that is created when you multiply the mass of something by how fast it is moving.
- Momentum = Mass ×Velocity
- So, Mass = Momentum/Velocity
|
8. Force is the product of –
(a) Mass and velocity
(b) Mass and acceleration
(c) Weight and velocity
(d) Weight and acceleration
[45th B.P.S.C. (Pre) 2001]
Ans. (b) Mass and acceleration
- A force can make an object with mass move faster or even start moving if it wasn’t moving before.
- This is called acceleration.
- Force (F) = Mass × Acceleration = m.a
|
9. If the number represents volume and surface area of a cube are equal, then the length of the edge of the cube in terms of the unit of measurement will be –
(a) 3
(b) 4
(c) 5
(d) 6
[I.A.S. (Pre) 1997]
Ans. (d) 6
- The volume of cube = l³ (Where l is the Length of Cubes edges)
- Surface area of cube = 6l²
- According to the question, both are equal to each other
- Therefore l³ = 6 l²
- Hence l = 6
|
10. Energy conservation means –
(a) Generation and destruction of energy
(b) Energy could be created
(c) Energy could not be created but destroyed
(d) Energy can neither be created nor destroyed
[M.P.P.C.S. (Pre) 2000]
Ans. (d) Energy can neither be created nor destroyed
- The Law of conservation of energy states that energy can’t be made out of nothing, and it can’t disappear either.
- It can only change from one form to another.
|
11. The energy of wind is –
(a) Only potential
(b) Only kinetic
(c) Electrical
(d) Potential and kinetic both
[Uttarakhand Lower Sub. (Pre) 2010]
Ans. (b) Only kinetic
- Anything moving has kinetic energy – energy caused by the motion or movement.
- Wind energy is the energy of air on the move.
- This kinetic energy of the wind can be turned into mechanical and electrical energy.
|
12. In wind power, which form of energy is converted into electrical energy?
(a) Kinetic energy
(b) Potential energy
(c) Solar energy
(d) Radiant energy
[U.P. PCS (Pre) 2016]
Ans. (a) Kinetic energy
- Wind energy is when the wind is used to create power.
- Wind turbines change the wind’s energy into mechanical power.
- This power can do certain jobs like grinding grain or pumping water.
- A generator can also turn the mechanical power into electricity.
|
13. Match List I with List II and choose the correct answer from the code given below list-I List –II
| (Energy Conversion) |
(Device/Mechanism) |
| A. Heat to electric |
1. Car Braking |
| B. Electric to sound |
2. Nuclear reactor |
| C. Mass to heat |
3. Loudspeaker |
| D. Chemical to heat and light |
4. Solar cell |
| |
5. Fuel combustion |
Code :
A B C D
(a) 1 2 3 4
(b) 4 3 2 5
(c) 2 1 3 5
(d) 3 1 2 4
[U.P.P.C.S. (Mains) 2002]
Ans. (b) 4 3 2 5
| (Energy conversion) |
(Device/mechanism) |
| Heat to electric |
Solar cell |
| Electric to sound |
Loudspeaker |
| Mass to heat |
Nuclear reactor |
| Chemical to heat and light |
Fuel combustion |
|
*14. Newton’s first law of motion is known as
(a) Gravity
(b) Law of Inertia
(c) Law of conservation of momentum
(d) Vertical motion
[Chhattisgarh P.C.S. (Pre) 2019]
Ans. (b) Law of Inertia
- Newton’s first law of motion, also known as the ‘Law of Inertia’, states that an object will stay still or keep going in one direction at the same speed unless something pushes it.
- Inertia is the tendency for an object to stay still or keep going in the same way unless something acts on it.
|
*15. As the train starts moving, the head of the passenger sitting inside leans backward because of –
(a) Inertia of Rest
(b) Inertia of Motion
(c) Moment of Inertia
(d) Conservation of Mass
[U.P. U.D.A./L.D.A. (Pre) 2010]
Ans. (a) Inertia of Rest
- Newton’s first law of motion, also known as the law of inertia, states that an object which is not moving will stay still and an object that is already moving will keep going in the same direction and speed unless something else affects it.
- When a train begins moving, the passengers tend to fall backwards because the lower part of their body which is touching the train moves forward, while the upper part stays still because of inertia.
- This causes the upper part to be left behind and fall backwards.
|
*16. Static science is associated with –
(a) Dynamic situation
(b) Situation of rest
(c) Mental situation
(d) Data analyzing
[M.P. P.C.S. (Pre) 2012]
Ans. (b) Situation of rest
- Static science is a part of mechanics that studies objects that are not moving.
|
*17. Assertion (A): A man standing on a completely frictionless surface can propel himself by whistling.
Reason (R): If no external force acts on a system, its momentum cannot change.
Code :
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is not a correct explanation of A
(c) A is true but R is false
(d) A is false but R is true
[I.A.S. (Pre) 2000]
Ans. (b) Both A and R are true but R is not a correct explanation of A
- Newton’s third law states that for every action there is an equal and opposite reaction.
- When a man whistles, he uses his breath to push himself forward.
- Momentum is the combination of mass and motion.
- Therefore, if no external force is applied, the momentum will not change.
- Statement A and R are both correct, but R does not explain A correctly.
|
18. It is more difficult to walk on the ice than on the road because :
(a) Ice is harder than the road.
(b) The road is harder than the ice.
(c) Ice does not offer any reaction when we push it with our foot.
(d) Ice has a lesser friction than the road.
[U.P.P.C.S. (Pre) 1994]
Ans. (d) Ice has a lesser friction than the road.
- Walking on ice is harder than walking on the road because ice has less friction.
- The road’s surface is rough, which helps you to keep moving forward.
|
*19. Consider the following statement and conclusions which can be drawn from it. Choose the correct conclusion.
Statement: In starting a loaded cart, one has to push harder than to keep it moving.
Conclusion :
(a) The weight of a moving object is less.
(b) The wheels tend to slip initially.
(c) There is less friction once the cart starts moving.
(d) Practice makes perfect.
[U.P.P.C.S. (Mains) 2013]
Ans. (c) There is less friction once the cart starts moving.
- It is harder to start an object moving than it is to keep it moving once it is in motion.
- This is why it can be hard to slide a heavy box across the floor, but once it starts moving it gets easier to push.
- This is because the friction that holds an object in place is greater than the friction that slows down a moving object.
|
20. For every action there is an equal and opposite reaction. The law was given by :
(a) Newton
(b) Albert Einstein
(c) Bohr
(d) Handane
[U.P. R.O./A.R.O. (Mains) 2017]
Ans. (a) Newton
- Newton’s third law of motion states that for every action, there is a reaction that is equal and opposite.
- This means that when two objects interact, they both experience an equal force, but in opposite directions.
|
21. A man jumped at a speed of 5 meters per second from a stationary boat and the boat moved off at the speed of 0.5 meters per second. How many times is the mass of the boat greater than that of the man?
(a) 5.5 times
(b) 4.5 times
(c) 2.5 times
(d) 10 times
[I.A.S. (Pre) 1994]
Ans. (d) 10 times
- Let the mass of the person is M and the mass of the boat is N, then the momentum of the boat + momentum of the person before Jump = 0
- then Momentum of both after man’s jump = M × 5 – N × 0.5
- ⇒ M × 5 – N × 0.5 = 0 (According To The Principle of Conservation of Momentum)
- N × 0.5 = M × 5 ⇒ N/M = 5/0.5 = 10
- Thus mass of the boat is 10 times greater than that of the man.
|
22. A truck, a car, and a motorcycle have equal kinetic energies. If equal stopping forces are applied and they stop after traveling a distance of X, Y, and Z respectively, then –
(a) X > Y > Z
(b) X < Y < Z
(c) X = Y = Z
(d) X 4Y 8 Z
[I.A.S. (Pre) 1996]
Ans. (c) X = Y = Z
- If the same amount of energy and force is used, the objects will stop at the same place.
- Therefore, X, Y, and Z are the same.
|
23. The ratio of kinetic energies of two bodies of the same mass is 4: 9, the ratio of their velocities will be
(a) 4: 9
(b) 2 : 3
(c) 16: 81
(d)√2:√3
[U.P. R.O./A.R.O. (Pre) 2017]
Ans. (b) 2 : 3
- As per the question, the mass of both bodies is the same. Suppose, the velocity of body I is v1 and Velocity of the body II is v2.
- Kinetic Energy of the body I (K1) = 1/2 mv1²
- Kinetic Energy of the body II (K2) = 1/2 mv2²
- K1/K2 = ½mv1²/½ mv2² = v1²/v2²
- According to the question,
- K1/K2 = 4/9 ⇒ v1²/v2² = 4/9 ⇒ (v1/v2) = 4/9
- ⇒ v1/v2 = √4/√9 =2/3= 2:3
|
24. Cycles and cars use ball bearings, because-
(a) The actual area of contact between the wheel and axle is increased.
(b) The effective area of contact between the wheel and axle is increased.
(c) The effective area of contact between the wheel and axle is reduced.
(d) None of the above statements is correct.
[I.A.S. (Pre) 2013]
Ans. (c) The effective area of contact between the wheel and axle is reduced.
- A ball bearing’s job is to make it easier to turn things around and help them hold up heavy loads.
- The ball bearing will reduce the amount of contact between the wheel and axle, which means it also reduces the amount of friction.
|
25. A person is sitting in a car which is at rest. The reaction from the road at each of the four wheels of the car is R. When the car runs on a straight level road, how will the reaction at either of the front wheels vary?
(a) It will be greater than R
(b) It will be less than R
(c) It will be equal to R
(d) It shall depend on the material of the road
[I.A.S. (Pre) 2008]
Ans. (b) It will be less than R
- The amount of friction when an object is moving is related to the adhesion reaction and is less than when it is still.
- So, option (b) is the right choice.
|
26. An oil tanker is partially filled with oil and moves forward on a level road with uniform acceleration. The free surface of oil then –
(a) Remains horizontal
(b) Is inclined to the horizontal with a smaller depth at the rear end
(c) Is inclined to the horizontal with a larger depth at the rear end
(d) Assumes parabolic curve
[I.A.S. (Pre) 2003]
Ans. (c) Is inclined to the horizontal with a larger depth at the rear end
- When an oil tanker is not full of oil and is driving on a flat road while speeding up, the oil inside the tanker will tilt towards the back end with more oil at the back than the front.
|
27. Consider the following statements : A 4-wheel vehicle moving in a sharp circular path at high speed will :
1. Overturn about its outer wheels
2. Overturn about its inner wheels
3. Skid outwards
4. Skid inwards
Which of these statements are correct?
(a) 1 and 3
(b) 2 and 4
(c) 2 and 3
(d) 1 and 4
[I.A.S. (Pre) 2003]
Ans. (a) 1 and 3
- Tanθ = v²/rg
- θ = Inclination from normal
- r = Radius of the circular path
- v = Velocity of vehicle
- If a car is going too fast, it will slide outward.
- The friction between the road and the car’s tires will provide the force needed to make it move in a curved path.
- If the outside of the turn is not raised, the car will slide outward and turn over its outside wheels.
|
28. A batsman hits a cricket ball which then rolls on a level ground. After covering a short distance, the ball comes to rest. The ball slows to a stop because
(a) The batsman did not hit the ball hard enough
(b) Velocity is proportional to the force exerted on the ball
(c) There is a force on the ball opposing the motion
(d) There is no unbalanced force on the ball, so the ball would try to come to rest
[M.P.P.C.S. (Pre) 2017]
Ans. (c) There is a force on the ball opposing the motion
- A cricket player hits the ball.
- It rolls on the ground for a bit, but then stops because something is pushing against it and slowing it down – that thing is called friction.
- If there was no friction, the ball would keep going.
|
29. What is the correct equation for finding the acceleration?
(a) a = v-u/t
(b) a = u + vt
(c) a = v+u/t
(d) a= v+u/2
[U.P.P.S.C. (Pre) 2003]
Ans. (a) a = v-u/t
- As we know v = u + at or at = v – u
- a = v-u/t
- where, v = final velocity of the particle
- u = initial velocity of the particle
- a = acceleration, t = time
|
30. The working principle of a washing machine is :
(a) Centrifugation
(b) Dialysis
(c) Reverse osmosis
(d) Diffusion
[I.A.S. (Pre) 1997, U.P.P.C.S. (Mains) 2004, Uttarakhand Lower Sub. (Pre) 2010]
Ans. (a) Centrifugation
- A washing machine works by spinning the water and clothes around really fast.
- This process, called centrifugation, separates the dirt from the clothes based on size, shape, density, and other factors.
|
31. The separation of cream from milk by churning is due to –
(a) Gravitational force
(b) Cohesive force
(c) Centrifugal force
(d) None of the above
[Jharkhand P.C.S. (Pre) 2013]
Ans. (c) Centrifugal force
- Spinning milk in a churn causes the cream to separate from the milk because of centrifugal force.
|
