Answer:
a) ![v=0.5405\ m.s^{-1}](https://tex.z-dn.net/?f=v%3D0.5405%5C%20m.s%5E%7B-1%7D)
b) ![v_p'=0.1143\ m.s^{-1}](https://tex.z-dn.net/?f=v_p%27%3D0.1143%5C%20m.s%5E%7B-1%7D)
Explanation:
Given:
mass of ball, ![m_b=4\ kg](https://tex.z-dn.net/?f=m_b%3D4%5C%20kg)
initial speed of the ball, ![v_b=10\ m.s^{-1}](https://tex.z-dn.net/?f=v_b%3D10%5C%20m.s%5E%7B-1%7D)
mass of the person, ![m_p=70\ kg](https://tex.z-dn.net/?f=m_p%3D70%5C%20kg)
a)
Using the conservation of linear momentum:
When the person catches the ball, assuming that the person catches it with an impact without absorbing the shock.
![m_b.v_b=(m_b+m_p)v](https://tex.z-dn.net/?f=m_b.v_b%3D%28m_b%2Bm_p%29v)
![4\times 10=(4+70)\times v](https://tex.z-dn.net/?f=4%5Ctimes%2010%3D%284%2B70%29%5Ctimes%20%20v)
![v=0.5405\ m.s^{-1}](https://tex.z-dn.net/?f=v%3D0.5405%5C%20m.s%5E%7B-1%7D)
b)
When the ball hits the person and bounces off with the velocity of
.
Using the conservation of linear momentum:
![m_b.v_b+m_p.v_p=m_b.v_b'+m_p.v_p'](https://tex.z-dn.net/?f=m_b.v_b%2Bm_p.v_p%3Dm_b.v_b%27%2Bm_p.v_p%27)
where:
final speed of the ball after collision
final speed of the person after collision
initial velocity of the person = 0
putting the respective values in the above eq.
![4\times 10+0=4\times 8+70\times v_p'](https://tex.z-dn.net/?f=4%5Ctimes%2010%2B0%3D4%5Ctimes%208%2B70%5Ctimes%20v_p%27)
![v_p'=0.1143\ m.s^{-1}](https://tex.z-dn.net/?f=v_p%27%3D0.1143%5C%20m.s%5E%7B-1%7D)
Answer:
a= (-g) from the moment the ball is thrown, until it stops in the air.
a = (0) when the ball stops in the air.
a = (g) since the ball starts to fall.
Explanation:
The acceleration is <em>(-g)</em> <em>from the moment the ball is thrown, until it stops in the air</em> because the movement goes in the opposite direction to the force of gravity. In the instant <em>when the ball stops in the air the acceleration is </em><em>(0)</em> because it temporarily stops moving. Then, <em>since the ball starts to fall, the acceleration is </em><em>(g)</em><em> </em>because the movement goes in the same direction of the force of gravity
Answer:
Option A is correct.
Explanation:
In the given triangle , x is the base and 14 is the hypotenuse for angle 33°.
cos 33 = base / hypotenuse
Putting the given values
cos 33 = x / 14
.84 = x / 14
x = .84 x 14
= 11.7
Option A is correct.