A ball is projected horizontally from the top of a cliff on the surface of the earth with a speed of 40 ms-1. Assuming that there is no air resistance, what will be its speed after 3s?
Correct answer: C. 70 ms-1
- A. 30 ms-1
- B. 40 ms-1
- C. 70 ms-1
- D. 60 ms-1
Explanation
Option C is correct.The horizontal velocity of the ball will be the same 3 seconds later. This is because there is no force acting on the ball in the horizontal direction. The vertical velocity of the ball will increase by 30 m/s after 3 seconds. This is because the acceleration due to gravity is 10 m/s² and the ball has been falling for 3 seconds. The speed of the ball 3 seconds later will be: Horizontal Velocity = 40m/sVertical Velocity = 30m/s Speed = Horizontal Velocity + Vertical Velocity = 40 m/s + 30 m/s = 70 m/s Therefore, the speed of the ball will be 70 m/s 3 seconds later.
Last updated
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.
Exams that ask Physics questions like this
Physics is on 13 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
Related questions
(1, 1, 1) . (2, 2, 2)
1st law of motion gives the definition of:
2nd law of motion measures which quantity?
7.0 kg bowling ball experience a net force of 5.0N. What will be its acceleration?
A 0.2 kg rubber ball is dropped from the window of a building. It strikes the sidewalk below at 30m/s and rebounds up at 20m/s. The impulse on the ball during the collision is: