Question

A) A particle moves halfway around a circle of radius R. It is acted on by a radial force of magnitude F. The work done by the radial force is

A. zero

B. FR

C. FπR

D. 2FR

E. 2πR

B) 2. A constant force of 45 N directed at angle θ to the horizontal pulls a crate of weight 100 N from one end of a room to another a distance of 4.0 m. Given that the vertical component of the pulling force is 12 N, calculate the work done by the force in moving the crate.

A. 4.1 × 10^2

B. 4.8 × 10
C. 3.9 × 10^2 N/m

D. 1.7 × 10^2

E. 3.9 × 10^3 J

C)3. Two identical crates with 100 kg mass are being pushed up at a constant speed an inclined plane that is at the angle of 20 degrees above the horizontal. One plane is frictionless, while the coefficient of friction between the crate and the other incline is 0.20. What is the absolute difference in work needed to push the crate a distance of 2.0 m along each plane?

A. 670 N

B. 1040 N

C. no difference

D. 370 N

E. 134 N

Answer 1