An object is thrown vertically upwards and rises to a height of 10 m. Calculate
(i) the velocity with which the object was thrown upwards and (ii) the time taken by the object to reach the highest point.

Options

A. 12 m/s, 1,43 s
B. 1 m/s, 1.84 s
C. 14 m/s, 1.43 s
D. 12 m/s, 1.84 s

Answer

C

Explanation

Height raised, h = 10 m
Final velocity, v = 0m/s
Acceleration due to gravity, `g = 9.8 m//s^2`
Acceleration due to object, `a=-9.8 m//^s2`
Now, we know that `v^2 =u^2 + 2ah`
`0=u^2+2xx(-9.8) xx 10 `
`-u^2 =-2 xx 9.8 xx10`
`u=sqrt(196)m//s`
`=14m//s`
Also, `v= u+at`
`0=14m//s-9.8 m//s^2 xxt`
`implies t = 1.43` s