Question

1. a) In long jump does it matter how high you jump? State the factors that determine the span of the jump. b) A bullet of mass 20 g is fired horizontally into a suspended stationary would block of mass 380 g with a velocity of 200 ms-1 . What is the common velocity of the bullet and block if the bullet is embedded in the block? If the block and bullet experience a constant opposing force of 2 N, find the time taken by them to come to rest.

2. a) A lunar landing module is descending to the Moon’s surface at a steady speed of 10 ms-1 . At a height of 120 m, a small object falls from its landing gear. Taking the Moon’s gravitational acceleration as 1.6 ms-2 , at what speed, in ms-1 , does the object strike the moon? b) A ball A of mass 0.1kg, moving with a velocity of 6 ms-1 , collides directly with a ball B of mass 0.2 kg at rest. Calculate the common velocity if both balls move off together. If A had rebounded with a velocity of 2 ms-1 , in the opposite direction after collision, what would be the new velocity of B?

Answer 1

1.a. No, the height of the jump is not important in high jump. The span depends only on two factors: magnitude of velocity(speed) and the angle at which the person takes off. More is the speed, more is the span. On the other hand, span increases till the angle increases to 45 degrees and then decreases with angle.