Help me pls An object accelerates if it:

a.) changes the direction of its velocity but not the magnitude

b.)changes the magnitude of the velocity but not the direction

c.)changes its speed

d.) all of the above

e.) none of the above

Acave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. the lift is performed in three stages, each requiring a vertical distance of 10.0 m: (a) the initially stationary spelunker is accelerated to a speed of 4.90 m/s; (b) he is then lifted at the constant speed of 4.90 m/s; (c) finally he is decelerated to zero speed. how much work is done on the 68.0 kg rescue by the force lifting him during each stage?

An object's buoyant force and weight mean the same thing.a. trueb. false

Which of the following is the phase that results when the moon is on the opposite side of the earth from the sun? a. quarter moon b. crescent moon c. new moon d. full moon