Question

A car falls of a ledge and drops to the ground in 0.5 s. Let g= 10 ms-2
a. What is its speed on touching the ground?
b. What is its average speed during 0.5s?
c. How high is the ledge from the ground?

Answer 1

Time , t= 1/2 s
Initial velocity ,u= 0 m/s
Acceleration due to gravity g = 10m/ssquare
Acceleration of the car a= 10 m/s square (downward)
Speed v= at
v= 10^ 0.5 =5m/s

Average speed =u+v/2
0+5/2
2.5m/s

Distance travelled,s= 1/2at square
1/2^t^(0.5) square
1/2^10^ 0.25m
Thus,
Its average speed on striking the ground is 5m/s
Its average speed during the 0.5s is 2.5m/s
Height of the ledge from the ground is 1.25m