4. edna stands at the top of a tall cliff. she throws a stone upwards with an initial speed of 15 m/s. she then throws
a stone downwards with the same speed. both stones strike the ground below at the same location. neglecting air
resistance, which statement below is true?
a the stone thrown down will hit the ground with the greatest velocity.
b. the stone thrown up will hit the ground with the greatest velocity.
c. both stones will strike the ground with the same velocity.
d. both stones will strike the ground after being in the air the same amount of time.

A12-kg bag of groceries is tossed onto a table at 4.0 m/s and slides to a stop in 2.2 s . modify the equation fδt=δ (mv) to find the force of friction.

Next a skier is pulled by a tow rope up a frictionless ski slope that makes an angle of 15 with the horizontal. the rope moves parallel to the slope with a constant speed of 0.69 m/s. the force of the rope does 800 3 of work on the skier as the skier moves a distance of 8.4 m up the incline. (a) if the rope moved with a constant speed of 2.2 m/s how much work would the force of the rope do on the skier as the skler moved a distance of 8.4 m up the incline? at what rate is the force of the rope doing work on the skier when the rope moves with a speed of (b) 0.69 m/s and (c) 2.2 m/s?

Why do different substances have diffrent properties