Physics Module 9

Either increase or decrease

A box is pulled a distance, d, across a floor by a force F, which makes an angle, θ, with the horizontal. If the magnitude of the force were decreased and the angle was decreased, the work done by the force would:

False

Work is done on dishes when you pull a tablecloth out from under them and they remain in place.

False

Useful work is the work done by an external system.

True

Work is done on an object as you drop it from the second floor of a building to the ground floor.

W=F x d x cos (0)

If the force and displacement are not collinear, which formula is used for work?

Increase

A box is pulled a distance, d, across a floor by a force F, which makes an angle, θ, with the horizontal. If the magnitude of the force increased and the angle was decreased, the work done by the force would:

48.0 N

A weight is placed on the spring in the graph below. What is the value of the weight if the spring compresses 12.0 cm?

31360 J and 7.50 kcal

A 80.0-kg person climbs several flights of stairs totaling 40.0 m. Find the work in J and kcal required to perform this task.

490 N/m

An object is hung on a spring scale to determine its mass. What is the spring constant if the scale stretches 2.00 cm for a 1.0 kg load?

400 N/m

What is the spring constant for the graph below?

40200 J

Calculate the work required to lift a 2000 kg vehicle on a lift, 2.0 m at constant speed, assuming friction averages 500 N.

980 J

A person pushes a 10.0 kg box 50.0 m at a constant speed on level ground, against a friction force. The coefficient of kinetic friction is 0.2. What is the work performed by the person to overcome the friction?

1.0 kg

A spring has a spring constant of 100 N/m. What is the mass of an object if spring stretches 10.0 cm?

10.0 N

A weight is placed on the spring in the graph below. What is the value of the weight if the spring compresses 5.0 cm?