A force that opposes motion between surfaces that are touching

What is the force required to lift the balloon with V=1500m3 and m=420kg, containing air with density 0.8kg/m3 and moving in air with density 1.3 kg/m3?

The force P is applied to the 59-kg block when it is at rest. Determine the magnitude and direction of the friction force exerted by the surface on the block if (a) P = 0, (b) P = 198 N, and (c) P = 288 N.

For each group of terms, write a sentence that shows how the terms are related using position: time: motion

Mirrors light, prisms light

How many millimeters are there in one centimeter

For a stationary observer, when the source of a sound is moving, its pitch appears to change.

Give an example of each simple machine

The product PV, where P and V represent pressure and volume respectively, is a unit for which? A entropy B force C impulse D work

IF it possible for an object to move for 10 seconds at a high speed and end up with an average velocity of zero? true or false

The boy moving down the hill posses what energy?