Physics: which action requires no work by a weightlifter? a.) lifting a weight from the floor to above his head b.) pushing a weight across the floor c.) setting the weight down on the floor d.) carrying a weight 1m across a level surface

Heterogeneous mixture with larger particles that never settle is

The friction of the water on a boat produces an acceleration of -10. m/s2. if the boat is traveling at 30. m/s and the motor is shut off, how long it take the boat to slow down to 5.0 m/s?

Ablock of mass m slides on a horizontal frictionless table with an initial speed v0 . it then compresses a spring of force constant k and is brought to rest. the acceleration of gravity is 9.8 m/s2 . how much is the spring compressed x from its natural length?