A stone is thrown vertically upward from ground level with speed of 25m/s. At what time is it 5m above the ground.

Question

asked Nov 14, 2023 219k views

1 Answer

Farrellw · Answer 1 · 2023-11-18T06:21:42+0000

Answer:

The stone will be
above the ground in
2.3s

Step-by-step explanation:

As the stone is thrown vertically upward from ground with speed i.e.,

the initial velocity,
u=25m/s ,

the final velocity,
v=0m/s ,

acceleration due to gravity,
a = -10m/s^2 (upward motion)

$v=u+at\\0=25+(-10)t\\0=25-10t\\t=2.5s$

To calculate the height at which the stone reached above the ground we can use the below formula:

s=ut+(1)/(2)at^2

s=25*2.5+(1)/(2)(-10)(2.5)^2

s=62.5-5*6.25=62.5-31.25=31.25m

Now, the time taken by stone to reach
above the ground can be calculated using

$u=0m/s\\s=31.25-5=26.25m\\a=10m/s^2\\t=?$

$s=ut+(1)/(2) at^2\\$

26.25=0 * t+(1)/(2) * 10 * t^2

26.25=0+5t^2

5t^2=26.25

t^2=(26.25)/(5)=5.25

t=√(5.25) =2.3s

Thus, at
2.3s the stone will reach
above the ground.