Question

A ball is thrown vertically upwards with the velocity of 49m/s. Calculate the time taken by it to reach the topmost point. Use: g=10m/s2

Answer 1

Answer:

A ball is thrown vertically upwards with a velocity of 49m/s. The time taken by it to reach the topmost point is $4.9\ s$

Explanation:

• According to the first equation of motion,

        $\mathrm{v}=\mathrm{u}+\mathrm{at}$            ...(1)

• According to the third equation of motion,

        $\mathrm{v}^{2}-\mathrm{u}^{2}=2 \mathrm{aH}$     ...(2)

Where

u - Initial velocity of the object

v - Final velocity of the object

a - acceleration

t -  time taken

From the question,

$u = 49\ m/s$

$v =0$

$a = g =- 10\ m/s^2$  (since ball throw vertically upward)

Substitute all these values into equation (2)

$0-(49)^{2}=2 \times(-10) \times \mathrm{H}$

$H = \frac{49^{2} }{20} = 120.05$

Now consider equation(1),

$0=49-10 \mathrm{t}$

$t = 4.9 \ s$