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The cutting cord on a gas-powered weed cutter is 0.16 m in length.  If the motor rotates at the rate of 20 rev/s, what is the approximate linear speed of the end of the cord?

A 7.6 kg chair is pushed across a frictionless floor with a force of 42 N that is applied at an angle of 22° downward from the horizontal. What is the magnitude of the normal force on  the chair?

A bullet with mass 12.0g  travels 415 m/s. Find its kinetic energy. ( Hint: Convert 12.0 g to kg )  

A car is negotiating a flat circular curve of radius 50 m with a speed of 20 m/s.  The maximum centripetal force (provided by static friction) is 1.2 × 104 N. What is the centripetal acceleration of the car?

True or False: Electric force is a contact force.

A 500-kg sack of coal is dropped on a 2000-kg railroad flatcar which was initially moving at 3m/s as shown. After the sack rests on the flatcar, the speed of the flatcar is:

A 200-N/C electric field is in the positive x direction. The force on an electron ( 1.60 x 10 -19 C)  in this field is:

A rocket moves through empty space in a straight line with constant speed.  It is far from the gravitational effect of any star or planet.  Under these conditions, the force that must be applied to the rocket in order to sustain its motion is

The kinetic energy of a motorcycle and rider is 60,000 J. If  their total  mass is 300 kg, what is their speed?    

Suppose that Paul D. Trigger fires a bullet from a gun. The speed of the bullet leaving the muzzle will be the same as the speed of the recoiling gun ____.