VISUAL PHYSICS ONLINE

5 ADVANCED MECHANICS

PROJECTILE MOTION

P50 1901

A ball is a projected from ground level by a tennis ball launcher.

(A)

Draw an arrow which represents the velocity of the ball at (1) its launch, (2) at its maximum height, (3) just before ball hits the ground.

(B)

At what angle should the launcher be set at so that the ball reaches its (1) maximum height, (2) maximum range?

(C)

The launcher was set to project the ball at angle with respect to the ground with speed u. If the launcher was adjusted so the ball was project at speed 2u, by what factor does (1) the ball’s maximum height increase, (2) the range of the ball increase?

(D)

The launcher was set to project the ball at angle 30^o with respect to the ground with speed u. When launched the ball travelled a horizontal distance R just before it the ground. The launcher was adjusted so the launch angle was 60^o. What was the horizontal distance travelled by the ball before it hit the ground?

(E)

What is the acceleration of the ball (1) just after it is launched, (2) at its maximum height, (3) just before it hits the ground. For each of the three cases, draw an arrow to represent the ball’s acceleration.

Projectile Motion Link

View solution below only after you have completed answering the question. The solution is not in a form that you would answer in an examination. The answers are often in more detail to help improve your appreciation and understanding of the physics.

Solution

(A)

(B)

(C)

(D)

The range of the ball is given by

So launch angles of 30^o and 60^o will give the same range R.

(E)

In flight, the acceleration of the ball is always