How much work in joules must be done to stop a 920-kg car traveling at 90 km/h?
1 answer:
Answer:
Work done, W = −287500 Joules
Explanation:
It is given that,
Mass of the car, m = 920 kg
The car is travelling at a speed of, u = 90 km/h = 25 m/s
We need to find the amount of work must be done to stop this car. The final velocity of the car, v = 0
Work done is also defined as the change in kinetic energy of an object i.e.
W = −287500 Joules
Negative sign shows the work done is done is opposite direction.
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Answer:
The ball traveled 0.827 m
Explanation:
Given;
distance between the metal plates of the room, d = 3.1 m
mass of the glass, m = 1.1g
charge on the glass, q = 4.7 nC
speed of the glass ball, v = 4.8 m/s
voltage of the ceiling, V = +3.0 x 10⁶ V
The repulsive force experienced by the ball when shot to the ceiling with positive voltage, can be calculated using Coulomb's law;
F = qV/d
|F| = (4.7 x 10⁻⁹ x 3 x 10⁶) / (3.1)
|F| = 4.548 x 10⁻³ N
F = - 4.548 x 10⁻³ N
The net horizontal force experienced by this ball is;
The work done between the ends of the plate is equal to product of the magnitude of net force on the ball and the distance traveled by the ball.
W = K.E
Therefore, the ball traveled 0.827 m