If the body of mass 2 kg dropped from the height of 5 m find its momentum (g =10ms-2):
Correct answer: B. 20 N s
- A. 15 N s
- B. 20 N s
- C. 30 N s
- D. 40 N s
Explanation
To solve this problem, we first calculate the final velocity of the body using the principle of conservation of energy. The gravitational potential energy at the height of 5 m is converted into kinetic energy as the body falls.The potential energy (PE) at the height can be given as PE = mgh = 2 kg * 10 m/s2 * 5 m = 100 J.This energy is converted into kinetic energy (KE), which is KE = 0.5 * m * v2. Equating the two gives: 100 = 0.5 * 2 * v2. Solving for v gives v = √(2 * 10 * 5) = √100 = 10 m/s.The momentum (P) is calculated using the formula P = mv = 2 kg * 10 m/s = 20 N s.Option A (15 N s) and Option C (30 N s) do not match the calculated momentum. Option D (40 N s) is a significant overestimate, possibly from a miscalculation. Therefore, Option B is the correct choice.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Force and Motion
Displacement, velocity and acceleration describe motion, including the horizontal and vertical components of projectile motion. The chapter connects these quantities with Newton's laws, momentum and impulse, then applies conservation of momentum to collisions, distinguishing elastic collisions from inelastic ones.
Practise Force and Motion
1,416 free Force and Motion MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Force and Motion questions
Two forces, one with a magnitude of 3N and the other with a magnitude of 5N, are applied to an object. For which orientations of the forces shown in the diagrams is the magnitude of acceleration of object is least?
In the case of a projectile fired at an angle equally inclined to the horizontal and vertical with velocity "u", the horizontal range is:
If the acceleration of a body is zero then the slope of its v-t graph:
A 2.5 kg stone is released from rest and falls toward Earth. After 4.0 s, the magnitude of its momentum is (g = 10ms-2):
Two objects moving along the opposite direction with different mass but same velocity. there relative velocity becomes:
A force of 10N acts on a body of mass 20kg for 10 seconds. The change in its momentum is