Question

physics problem

Answer 1

Anyone q. 3 solve it

Answer 2

@AZ see it

Answer 3

Have you tried? Where are you stuck

Answer 4

yes. i have tried

Answer 5

What exactly did you try?

We have an object that's dropped from a height h

The last 30 meters of descent take it 1.5 seconds to reach the ground.

Answer 6

Yes, I have tried. After 45 mins I solved it.

Answer 7

So first, calculate the velocity of the ball when it is 30 meters above the ground

\( \Delta x = v_0t + \dfrac{1}{2}at^2\)

We know that \(\Delta x = 30\) and that t = 1.5 s
a is going to be 9.8 m/s^2 since it's freefall

\( v_0\) will be the velocity when the ball is 30 meters high

Answer 8

once you calculate the velocity of the ball at 30 meters, we can use the fact that when the ball is initially dropped- the velocity is 0 and then by the time it's 30 meters from the ground, you have that velocity which you just calculated

so we have this formula
\( v = v_0 + at\)

your \( v\) is going to be the velocity you calculated when it's 30 meters above the ground
\( v_0\) is going to be 0 since that is the initial velocity when you drop the ball

so now you solve for t which is the total time it took for the ball to drop from a height of 'h'

Answer 9

and finally you'd use this formula again

\(\Delta x = v_0t + \dfrac{1}{2}at^2\)

\(\Delta x\) is going to be the 'h' we are looking for
the initial velocity of the ball \(v_0\) when it was dropped it 0
a = 9.8 m/s^2
t is the time it took for the ball to drop from the height of h which you just calculated previously

Answer 10

Kindly check it and tell me

Answer 11

@AZ

Answer 12

I think you shouldn't round 12.65 to 12.7 for the velocity of the object when it is 30 m high

\( v_0 = 12.65~ ms^{-1}\)

But yes, your method works too. It's actually shorter than what I suggested haha

Answer 13

Yes, you are right in round off method

Answer 14

I am thankfull to you @AZ for help.

Answer 15

It was my pleasure!