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kirill115 [55]
3 years ago
5

A tennis racket hits a tennis ball with a force of F=at−bt2, where a = 1200 N/ms , b = 370 N/ms2 , and t is the time (in millise

conds). The ball is in contact with the racket for 2.70 ms . If the tennis ball has a mass of 64.9 g , what is the resulting velocity of the ball, v, after the ball is hit by the racket? Express your answer numerically in meters per second to three significant fi
Physics
1 answer:
Veronika [31]3 years ago
4 0

Given Information:  

Mass of tennis ball = m = 64.9 g

Contact time = Δt = 2.70 ms

Force = F = at - bt²

a = 1200 N/ms

b = 370 N/ms²

Assuming that a and b is given as newton per milliseconds

Required Information:  

Velocity of the ball = Vf = ?  

Answer:  

Vf = 22.496 m/s

Explanation:  

The change in momentum of the ball is given by

Δp = -FΔt

Lets first find out the force acting on the tennis ball

F = aΔt - bΔt²

F = (1200)(2.70) - (370)(2.70)²

F = 542.7 N

Δp =  542.7*0.0027

Δp = 1.46 N.s

Δp = mVf - mVi

initial velocity is zero

Vf = Δp/m

Vf = 1.46/0.0649

Vf = 22.496 m/s

Therefore, the speed of the ball is 22.496 m/s

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Answer:

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You drive your car in a straight line at 15 m/s for 10 kilometers, then at 25 m/s for another 10 kilometers.
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Answer:

A) Average speed = 18.75 m/s

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Explanation:

Let the first distance be d1 and the second distance be d2.

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d2 = 10 km = 10000 m

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Answer:

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