Concept explainers
The "shot" used in the shot-put event is a metal ball with a mass of 7.3 kg. When thrown in Olympic competition, it is accelerated to a speed of about 14 m/s. As an approximation, let's say that the athlete exerts a constant force on the shot while throwing it and that it moves a distance of 3 m while accelerating.
(a) What is the shot's kinetic energy?
(b) Compute the force that acts on the shot.
(c) It takes about 0.5 s to accelerate the shot. Compute the power required. Convert your answer to horsepower.
(a)
The kinetic energy of the shot.
Answer to Problem 6C
The kinetic energy of the shot is
Explanation of Solution
Given:
The “shot” used in the shot-put event is a metal ball with a mass of
Formula used:
Kinetic energy is given as
Where,
Calculation:
We have,
Mass of shot,
Speed of shot,
Thus, kinetic energy of shot is calculated as
Conclusion:
Hence, the kinetic energy of the shot is
(b)
The force that acts on the shot.
Answer to Problem 6C
The force that acts on the shot is
Explanation of Solution
Given:
The “shot” used in the shot-put event is a metal ball with a mass of
Formula used:
There the four equations of motions, listed below:
Where,
Calculation:
Given that the shot is accelerated to a speed of about
Thus, we have
Using equation of motion, we have
Substituting the values, we get
Also, we know that force is calculated as
Substituting the values, we get
Conclusion:
Hence, the force that acts on the shot is
(c)
The “shot” used in the shot-put event is a metal ball with a mass of
Answer to Problem 6C
The power required is
Explanation of Solution
Given:
Given that shot used shot-put event is a metal ball with a mass of
Formula used:
There the four equations of motions, listed below:
Where
Also, Power is given as,
Calculation:
Given that the shot is accelerated to a speed of about
Thus, we have
Using equation of motion, we have
Substituting the values, we get
Also, we know that force is calculated as
Substituting the values, we get
Conclusion:
Hence, the power required is
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