Physics Help?????

Question

What is the maximum height that the given pebble reaches above its starting point and the angle?

 

A pebble is thrown with an initial velocity of 35.0 m/s at an unknown angle above the horizontal. When it reaches its highest point, its velocity is 33.0 m/s.

 

What is the maximum height that the given pebble reaches above its starting point and the angle?

 

I know you use the kinematics equation and plug in the given velocities for v final and v initial but my diagram and answer is way off from the solution. Would you be able to help?

Answer 1

step 1:

Initial velocity of pebble is 35.0 m/s .

Final velocity of the pebble is 33 m/s.

Find the maximum height :

The pebble is thrown with an initial velocity.

Consider the kinematics equation .

Where v is final velocity,

             u is initial velocity,

              g  ( 9.8 m/s² ) is acceleration of gravity.

Find the time at which pebble attains maximum height  : .

The time taken by pebble to reach maximum height is 0.204 sec.

step 2:

Now find the maximum height by kinematics equation .

Solution :

The maximum height reached by pebble is 6.938 m.

Answer 2

(b)

step 1:

Initial velocity of pebble is 35.0 m/s .

The maximum height formula in projectile motion with an angle A is .

Where u is initial velocity,

          A is the angle of projection,

          g  ( 9.8 m/s² ) is acceleration of gravity.

From the previous calculations maximum height 6.938 m.

Substitute h, u, A and g in maximum height formula.

So the angle of projection is 19.46°.

Solution :

The angle of projection is 19.46°.