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3 years ago

A tennis player practices against a wall, hitting a 0.1 kg ball towards the

Physics

1 answer:

pantera1 [17]3 years ago

3 0

Answer: 80 Newton

Explanation:

Initial velocity of ball = +20 m/s.

Final velocity of ball = -20 m/s

Mass of ball = 0.1kg

Time taken = 0.05 seconds

Average force = (Change in momentum of moving ball / Time taken)

Since, change in momentum = Mass (final velocity - initial velocity)

Change in momentum =0.1 x (-20 - (+20))

= 0.1 x (-20-20)

= 0.1 x (-40)

= -4.0 kgm/s

Then, put -4.0 kgm/s in the equation of force when Average Force = (Change in momentum / Time taken)

= (-4.0kgm/s / 0.05 seconds)

= 80Newton (note that the negative sign does not reflect on the magnitude of force)

Thus, the average force exerted on the ball is 80N

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Explanation:

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Two girls,(masses m1 and m2) are on roller skates and stand at rest, close to each other and face-to-face. Girl 1 pushes squarel

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Answer:

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$\vec{v}_{cm} = \frac{m_1\vec{v}_1 + m_2\vec{v}_2}{m_1 + m_2}$

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