## Tuesday, 23 September 2014

### Projectiles Problems

In all these questions ignore air resistance unless otherwise stated.

Question 1
 At t=0, a ball is thrown with an initial velocity of magnitude 15ms-1 at 75° to the horizontal (upwards). a) Calculate the magnitudes of the vertical and horizontal components of its initial velocity. b) Calculate the magnitude of the vertical component of velocity of the ball at t=0·5s. c) Calculate the magnitude of the vertical component of velocity of the ball at t=2·0s. Which way is the ball moving at this time? d) What is the magnitude of the horizontal component of velocity at t=2·0s?
Question 2
 A projectile is thrown upwards at 60° to the horizontal with an initial speed of 30ms-1, calculate a) the time taken for the projectile to return to its starting height b) the range of the projectile (the horizontal distance moved over a horizontal surface).
Question 3

 A ball is thrown upwards at 50° to the horizontal with an initial speed of 15ms-1. Calculate the magnitude of its velocity when it is at its maximum height.
Question 4

 A ball is thrown with a velocity of 25ms-1 horizontally. Find the magnitude and direction of its velocity after 1·25s (assuming that the ball has not reached the ground at this time).
Question 5

 An arrow is shot horizontally at a target 20m away. The arrow hits a point 19·6cm vertically below the point it was aimed at. Calculate the speed with which the arrow left the bow.