Work–energy theorem Transitional Reasoning Download PDF
10 Physics practice questions on Work–energy theorem. Questions that build towards applied reasoning.
Questions
- 1.
A maintenance crew uses a tow cable to pull a 1,000 kg service cart from rest along a straight horizontal track. The cable maintains a constant tension of 1,500 N directed at an angle of 60° above the horizontal, while a constant rolling resistance of 250 N opposes the motion. According to the work–energy theorem, what is the speed of the cart after it has traveled a horizontal displacement of 25 m?
- 2.
In an automated distribution center, a motorized pusher accelerates a 2.0 kg package from rest along a straight, frictionless horizontal guide rail. Over a distance of 5.0 m, the forward force exerted by the pusher increases linearly from 10 N at the starting point to 30 N at the end of the run. According to the work–energy theorem, what is the speed of the package at the end of this 5.0 m displacement?
- 3.
In a ballistic testing facility, a 0.050 kg metal probe strikes a composite target horizontally with an initial speed of 200 m/s. The probe first penetrates a 0.20 m thick outer layer that exerts a constant resistive force of 3,500 N opposing its motion. It then enters a denser backing layer that exerts a constant resistive force of 6,000 N, which brings the probe to a complete stop. According to the work–energy theorem, what distance does the probe penetrate into the backing layer?
- 4.
A development team conducts a dynamic track test on an 800 kg electric vehicle operating along a level roadway. In the first segment of the test, the vehicle accelerates from rest to 20 m/s. In the second segment, the vehicle accelerates further from 20 m/s to 30 m/s. According to the work–energy theorem, what is the net work done on the vehicle during the second segment?
- 5.
A safety engineering team evaluates the braking mechanism of a 500 kg test sled moving along a straight horizontal track. In Trial 1, the sled enters a deceleration zone at 20 m/s and is brought to a complete stop over a distance of 40 m by a constant retarding force. In Trial 2, the braking mechanism is adjusted to exert twice this retarding force, and the sled enters the zone at the same initial speed of 20 m/s. According to the work–energy theorem, what is the speed of the sled after traveling 15 m through this braking zone in Trial 2?
- 6.
A parcel with a mass of 10 kg is released from rest at the top of a straight loading ramp of length 5.0 m that descends through a vertical height of 3.0 m. The parcel slides down the ramp and reaches the bottom with a speed of 6.0 m/s. Assuming the acceleration due to gravity is 9.8 m/s² and the normal force does no work, what is the work done by the friction force on the parcel during this slide?
- 7.
A crane hoists a 250 kg shipping container vertically upward from rest. Over a vertical displacement of 4.0 m, the tension in the hoisting cable does +11,800 J of work while air resistance is negligible. Taking the acceleration due to gravity as 9.8 m/s², what is the speed of the container at the end of this 4.0 m displacement?
- 8.
A technician tests a 4.0 kg robotic transport sled moving along a straight horizontal track. Over a displacement of 8.0 m, the sled's electric motor performs +160 J of work while a constant kinetic friction force opposes the motion. If the sled accelerates from an initial speed of 2.0 m/s to a final speed of 6.0 m/s over this distance, what is the magnitude of the friction force acting on the sled?
- 9.
To test an automated braking mechanism, an engineering student directs a 4.0 kg remote-controlled cart into a horizontal deceleration lane with an initial kinetic energy of 72 J. A constant braking force acts parallel to the track, bringing the cart to a reduced speed of 3.0 m/s over a distance of 6.0 m. Applying the work–energy theorem, what is the magnitude of the constant braking force exerted on the cart?
- 10.
A test cart with a mass of 2.0 kg moves along a straight horizontal track with an initial speed of 2.0 m/s. An electric drive exerts a constant forward force of 12 N on the cart over a displacement of 3.0 m, while a constant friction force of 5.0 N opposes the motion. According to the work–energy theorem, what is the speed of the cart at the end of this 3.0 m displacement?