Question

A particle is projected up the ground with speed 25 m/s. It is at height 30 m at time t1 and t2. Find t1 + t2​

Answer 1

Answer:

5

Explanation:

use second equation of motion u will get a quadratic equation solve and you get t1 and t2

Answer 2

Answer:

t₁+t₂=5

Explanation:

In the question,

The speed of the projection of the particle is = 25 m/s

The height at which the particle is at times t₁ and t₂ is = 30 m.

So,

Now we know that,

$s=ut+\frac{1}{2}at^{2}$ (Second equation of motion)

So,

$30=(25)t-\frac{1}{2}(10)t^{2}\\So,\\12=10t-2t^{2}\\6=5t-t^{2}\\t^{2}-5t+6=0\\So,\\(t-3)(t-2)=0\\t=2,3$

So,

t₁ =2 seconds

t₂=3 seconds

So,

t₁+t₂=2+3=5 seconds

So,

t₁+t₂=5

Therefore, the sum of the time at which the particle is at the same height is 5 seconds.