Question

When a cricket ball is thrown vertically upwards, it reaches a maximum height of 15 metres. (a) What was the initial speed of the ball ? (b) How much time is taken by the ball to reach the highest point ? (g=10 ms -2

Answer 1

Answer:

The velocity of the cricket ball is 17.32 m/s

Time is taken by the ball to reach the highest point = 0.8660 seconds

Explanation:

The cricket ball can be seen and treated as a projectile in this case

The maximum height attained by a projectile in motion can be calculated using the formula:

$h = \frac{v^2 sin^2 \theta }{2g}$

In any projectile problem, once we know see that the object was released vertically upwards, we need to know that this means that the angle of projection is 90 degrees, and sin 90 is = 1

hence, h will be modified to become

$h = \frac{v^2 }{2g}$

$v = \sqrt{2gh}$

We are given that h = 15m and g = 10m/s2

$v = \sqrt{2 \times 10 \times 15} = 17.32m/s$

The velocity of the cricket ball is 17.32 m/s

B. We can get the time it took to reach the highest point by dividing

time = distance/speed

Time = 15/17.32 = 0.8660 seconds