POE - Forces and Moments Practice

Two kids are sitting on a see-saw. On one side, there is a person 3 m away from the fulcrum with a weight of 600 N. On the other side, is a person weighing 450 N. How far away must the second person sit in order for the see-saw to be at equilibrium?

• 4 m

• 2 m

• 3.5 m

• 5 m

Two swimmers on opposite sides of a boat attempt to turn the boat by pushing as shown. Determine the couple moment about point A on the bow.

• 100 Nm CW

• 100 Nm CCW

• 150 Nm CW

• 150 Nm CCW

A 100-lb vertical force is applied to the end of a lever which is attached to a shaft at O. Determine the moment about point O.

• 1200 lb⋅in CW

• 2400 lb⋅in CW

• 2078 lb⋅in CW

• 100 lb⋅in CW

Determine the moment about point O.

• 37.5 Nm CW

• 37.5 Nm CCW

• 100 Nm CW

• 100 Nm CCW

Determine the Moment about point O.

• 21 kN⋅m CCW

• 21 kN⋅m CW

• 28 kN⋅m CCW

• 28 kN⋅m CW

• 14 kN⋅m CCW

Determine the Moment about point A.

• 361.8 lb⋅in CW

• 260 lb⋅in CW

• 277.6 lb⋅in CW

• 322.4 lb⋅in CW

For a see-saw to balance, the anti-clockwise moment must equal the....

• clockwise moment

• weight

• gravity

• counterclockwise moment

Determine the moment about point B.

• 190.9 Nm CCW

• 190.9 Nm CW

• 203 Nm CCW

• 203 Nm CW

A lever, of length 1.5 m, is pivoted at one end. A force of magnitude 80 N acts at the other end of the lever. The angle between the lever and the force is 60. Find the moment of this force about the pivot.

• 103.9 Nm CCW

• 103.9 Nm CW

• 120 Nm CCW

• 120 Nm CW

• 60 Nm CCW

A bear travels 70 miles in a northeasterly direction from his den. It then travels 150 miles 60 degrees north of west. Determine how far and in what direction the bear is from his den.

• 181.2 mi @ 81 degrees North of West

• 181.2 mi @ 98.1 degrees North of West

• 218.4 mi @ 34.8 degrees North of West

• 218.4 mi @ 145.2 degrees North of West