A 537-kg trailer is hitched to a truck. Find the work done by the truck on the trailer in each of the following cases. Assume rolling friction is negligible. a. The trailer is pulled at constant speed along a level road for 2.30 km. b. The trailer is accelerated from rest to a speed of 88.8 km/h. c. The trailer is pulled at constant speed along a road inclined at 12.5° for 2.30 km.
(a)
The work done for by the truck on the trailer when the trailer is pulled at constant speed.
Answer to Problem 8PQ
The work done for by the truck on the trailer when the trailer is pulled at constant speed is
Explanation of Solution
Write the equation of work done.
Here,
At constant speed, the initial and final kinetic energy is same.
Conclusion:
Substitute,
Thus, the work done for by the truck on the trailer when the trailer is pulled at constant speed is
(b)
The work done for by the truck on the trailer when the trailer is pulled at 88.8km/h.
Answer to Problem 8PQ
The work done for by the truck on the trailer when the trailer is pulled at 88.8km/h is
Explanation of Solution
Write the equation of work done.
Here,
In this case, the initial kinetic energy is zero.
Write the expression for the final kinetic energy.
Here,
Rewrite the expression from equation (I).
Conclusion:
Substitute
Thus, the work done for by the truck on the trailer when the trailer is pulled at 88.8km/h is
(c)
The work done for by the truck on the trailer when the trailer is pulled at an angle
Answer to Problem 8PQ
The work done for by the truck on the trailer when the trailer is pulled at an angle
Explanation of Solution
Write the equation of work done.
Here,
Write the expression for the work done by gravity.
Here,
Rewrite the expression from equation (VIII).
Conclusion:
Substitute
Thus, the work done for by the truck on the trailer when the trailer is pulled at an angle
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Chapter 9 Solutions
Physics for Scientists and Engineers: Foundations and Connections
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