The work to be done to stop a car of mass 1200 kg and moving at a speed of 36 km/h is
Answers
Answer: 60000 J
Explanation:Mass of car= 1200 kg
Speed of car (initial)= 36 kmph
= 36*5/18 m/s
= 10 m/s
Now,
Work done= Change in kinetic energy
= 1/2 m( v1^2-v2^2)
=1/2 *1200(0^2-10^2)
= 600*(-10^2)
= 600*10
= 60000 J
Thank u.
Concept:
We need to utilize the kinetic energy concept since initially the car was in motion and have some amount of kinetic energy. The work done can be determined by the difference in kinetic energy.
Given:
Mass of car = 1200 kg
Speed of the car = 36 km/h
Find:
We need to determine the work done to stop the car
Solution:
Since the speed of the car is given in km/h, it first needs to be converted into m/s
Therefore, v = 36 km/h = 36 × 5/18 = 10 m/s
Since the car is in motion it shows kinetic energy of around, K.E = 1/2 mv²
Therefore, Kinetic energy = 1/2 (1200) × (10)²
Kinetic energy = 60,000 J
While the kinetic energy of the car when it comes to rest position is 0J
We know, Work done on an object = a change in kinetic energy
Therefore, Work done = 60,000 - 0
Work done = 60,000 J
Thus, the work to be done to stop a car is 60,000 Joules.
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