which of the following sentences about the velocity of an object is not true?

a. the object's velocity is a scalar quantity.
b. when the direction of motion changes, the velocity changes.
c. the object's velocity can be measured instantaneously or averaged.
d. when the speed of the object changes, the velocity of the object changes.

If you were to drop a rock from a tall building, assuming that it had not yet hit the ground, and neglecting air resistance. what is its vertical displacement (in m) after 6 s?

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?

Which of the following changes will result in a stronger electromagnet? a. using fewer coils of wire b. using a higher voltage c. using a shorter nail d. using a longer wire