Two balls A (mass M) and B (mass 2M) collide elastically. If A moves at 150 m/s and comes to rest, find velocity of B before collision. .
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2
3
4
Official Solution
Correct Option: (1)
Given elastic collision and A comes to rest: Use conservation of momentum: From coefficient of restitution:
02
PYQ 2022
medium
physicsID: ap-eapce
A ball of mass 300 g is dropped from a height of 10 m and penetrates 1.5 m into sand. Find the average resistance by the sand. Take .
1
35 N
2
23 N
3
34 N
4
28 N
Official Solution
Correct Option: (2)
Use energy conservation: Loss in kinetic energy = Work done by sand Total resistance = mg + extra resistive force
03
PYQ 2022
medium
physicsID: ap-eapce
A block of mass starts up a incline with an initial kinetic energy of . The coefficient of friction is . The distance it travels before coming to rest is:
1
2
3
4
Official Solution
Correct Option: (4)
Step 1: Use work-energy theorem. All kinetic energy is used against friction and gravity: Step 2: Total resisting force = Given:
-
- So:
Step 3: Let stopping distance be :
04
PYQ 2022
medium
physicsID: ap-eapce
A mass of 1 kg falls from a height of 1 m and lands on a massless platform supported by a spring with spring constant . The maximum compression of the spring is (take )
1
2 m
2
m
3
m
4
m
Official Solution
Correct Option: (1)
Energy conservation: Total gravitational potential energy is converted into spring potential energy at maximum compression.
Given:
Solving the quadratic:
05
PYQ 2022
medium
physicsID: ap-eapce
A lift raises 50 passengers of average weight each to a height of in time . If average power used is , then the value of is:
1
s
2
s
3
s
4
s
Official Solution
Correct Option: (4)
Step 1: Compute total work done: Each person exerts , so total weight = Height = Step 2: Given Power = Use:
06
PYQ 2022
medium
physicsID: ap-eapce
A bead of mass 400 g is moving along a straight line under a force delivering constant power 1.2 W. If the bead is initially at rest, the speed attained after 6 seconds is (in )
1
5
2
4
3
6
4
3
Official Solution
Correct Option: (3)
Power
Use work-energy theorem:
Given:
07
PYQ 2023
medium
physicsID: ap-eapce
A bullet of mass 20 g moving with is pierd 1 cm into a wooden block, then the retarding for experiend by the bullet is
1
2
3
4
Official Solution
Correct Option: (4)
The bullet has mass and initial velocity . It is stopped after traveling a distance . Since final velocity , we can use work-energy theorem or kinematics. The work done by the retarding force brings the bullet to rest, and is equal to its loss in kinetic energy. Using the work-energy theorem:
So, the retarding force is .
08
PYQ 2023
medium
physicsID: ap-eapce
The energy consumed by a 1000 W electric bulb when it is used for 1 hour is
1
3.6 W
2
3.6 J
3
3.6 W
4
3.6 J
Official Solution
Correct Option: (2)
The energy consumed by an electric device is given by: Where:
- (power of the bulb), - (time in seconds). Substituting the values: (Note: The unit of energy is Joules (J), not Watts (W), as Watt is the unit of power.) So, the energy consumed by the bulb is 3.6 J.
09
PYQ 2023
medium
physicsID: ap-eapce
A block of mass 5 kg moving on a rough surface with a velocity of 4 ms is stopped by the friction in 2 seconds. Then the coefficient of friction between the contact surfaces is:
1
0.4
2
0.3
3
0.5
4
0.2
Official Solution
Correct Option: (1)
We are given that the block has a mass , initial velocity , and is stopped by friction in . The acceleration due to gravity is . We first need to calculate the acceleration using the equation of motion:
Since the block is stopped, final velocity . Substituting the given values:
The negative sign indicates that the block is decelerating due to friction. Next, we use Newton's second law to find the frictional force :
Now, the frictional force is given by:
where is the coefficient of friction and is the acceleration due to gravity. Substituting the values:
Solving for :
Thus, the coefficient of friction between the contact surfaces is .
10
PYQ 2023
medium
physicsID: ap-eapce
A toy car of mass 100 g is moving with velocity of m/s, then the kinetic energy of the car is
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2
3
4
Official Solution
Correct Option: (3)
Mass . Velocity vector is , so speed:
Kinetic energy:
So, the kinetic energy of the toy car is J.
11
PYQ 2023
medium
physicsID: ap-eapce
When a spring of force constant is compressed by a force of , then the compression in the spring is
1
2
3
4
Official Solution
Correct Option: (2)
Hooke’s Law relates the force applied on a spring to its compression through the spring constant :
Given:
So, the compression in the spring is 5 cm.
12
PYQ 2023
medium
physicsID: ap-eapce
The speed of a body of mass 10 kg changes from 20 ms to 30 ms . The increase in the kinetic energy of the body is
1
1250 J
2
4500 J
3
2500 J
4
3000 J
Official Solution
Correct Option: (3)
The kinetic energy of a body is given by: Where:
- (mass of the body), - is the speed of the body. Initial kinetic energy ( ): Final kinetic energy ( ): The increase in kinetic energy is: So, the increase in the kinetic energy of the body is 2500 J.
13
PYQ 2025
medium
physicsID: ap-eapce
If a force F = (3i - 2j) N acting on a body displaces it from point (1 m, 2 m) to point (2 m, 0 m), then work done by the force is
1
5 J
2
6 J
3
4 J
4
7 J
Official Solution
Correct Option: (4)
The displacement vector is given by . The force vector is . Work done J.
14
PYQ 2025
medium
physicsID: ap-eapce
If a position dependent force acting on a body of mass 2 kg displaces it from to , then the work done by the force is
1
165 J
2
115 J
3
150 J
4
135 J
Official Solution
Correct Option: (4)
Work done by a variable force is given by: Given force: N, displacement from to . Calculate the integral: So, the work done by the force is 135 J.
