43
A ball is moving at 18ms\(^{-1}\) in a direction inclined at 60º to the horizontal. The horizontal component to its velocity is
- A. 9√3ms-1 ·
- B. 6√3ms-1 ·
- C. 8√3ms-1 ·
- D. 9ms-1 ·
44
The physical quantity that has the same dimensions as impulse is
- A. energy
- B. momentum
- C. surface tension
- D. pressure
45
The velocity of a sound wave at 27oC is 360ms-1. Its velocity at 127oC is
- A. 120√3 ms-1
- B. 240 ms-1
- C. 240√3 ms-1
- D. 720√3 ms-1
46
A bullet fired at a wooden block of thickness 0.15m manages to penetrate the block. If the mass of the bullet is 0.025kg and the average resisting force of the wood is 7.5 x 103N, calculate the speed of the bullet just before it hits the wooden block.
- A. 450ms-1
- B. 400ms-1
- C. 300ms-1
- D. 250ms-1