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:
a = 156.14 m/s^2
Explanation:
Using the laws of newton:
∑F = ma
where ∑F is the sumatory of forces, m the mass and a the aceleration.
so:
F - = ma
where F is the force from the hockey stick and is the force of friction.
Replacing values, we get:
(30.2N) - (3.5N)= (0.171kg)a
Finally, solving for a:
a = 156.14 m/s^2