# ^Projectile thrown straight up

^Projectile thrown straight up

Suppose a body is projected upwards from the ground and with the velocity u. The characteristics of motion of such a body are as follows.

1. The maximum height attained
2. Time taken to go up (ascent) = Time taken to come down (descent)
3. Time of flight
4. For an object thrown straight upwards with u = 50 m/s\
5. The speed of the body on return to the ground = speed with which it was thrown upwards
6. When the height attained is not large, that is u is not large, the mass, the weight as well as the acceleration remain constant with time its speed, velocity, momentum, potential energy and kinetic energy change with time.
1. Let m be the mass of the body. Then in going from the ground to the highest point, following changes take place.
• Change in speed = u
• Change in velocity = u
• Change in momentum = m u

Change in KE = Change in PE =

1. On return to the ground the changes in these quantities are as follows:
• Change in speed = 0
• Change in velocity = 2 u
• Change in momentum = 2 mu

Change in KE = Change in PE = 0

1. If the friction of air be taken into account, then the motion of the object thrown upwards will have the following properties:
• Time taken to go up (ascent) < time

taken to come down (descent)