Work (force)
What is the simplified integral expression for 'work' or W?
W= ∫a->b f(x)dx
What is the equation for Hooke's Law?
F=kx
How much work is done in lifting a 5-lb weight 4 feet off the ground?
20 ft-lb
A force of 10 N is required to hold a spring that has been stretched from its natural length by 5 cm. How much WORK is done?
F = (10 N/m)(0.05 m)
F = 0.5 N
W= (0.5)(0.5 m) = 0.25 J
How much work is done in lifting a 20-lb weight 6 feet off the ground?
120 ft-lb
How much FORCE is needed to pull a spring with a spring constant of 20 N/m a distance of 25 cm?
F=20 N/m * 0.25 m = 5 N
A variable force of (1/2)x moves an object along a straight line when it is x feet from the origin. How much work is done in moving the object from x=1 to x=3?
8 ft-lb
A spring is pulled to 10 cm and held in place with a force of 500 N. What is the spring constant of the spring?
500 N = k * .1 m
k=5000 N/m
A variable force of 5x^2 moves an object along a straight line when it is x feet from the origin. How much WORK is done in moving the object from x=1 ft to x=10 ft?
4.5 ft-lb
RECALL: A force of 40 N is required to hold a spring that has been stretched from its natural length of 10 cm to a length of 15 cm. How much WORK is done in stretching the spring from 15 cm to 18 cm?
1.56J