It always takes

to change the motion of an object.

O A.

electricity

OB.

energy

C.

gravity

D. density

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Why should galaxy collisions have been more common in the past than they are today? a. Galaxies attracted each other more strongly in the past because they were more massive; they had not yet turned most of their mass into stars. b.

Which force causes send dunes? A. Rivers B. Ice C. Wind D. Gravity

A wedge with an inclination of angle θ rests next to a wall. A block of mass m is sliding down the plane. There is no friction between the wedge and the block or between the wedge and the horizontal surface.

With what speed must m1 rotate in a circle of radius r if m2 is to remain hanging at rest?

Which term refers to the upper part of a glacier that receives the most snowfall? A. accumulation zone B. ablation zone C. terminus D. arete

Solve each problem. Be sure to show your work and give a final answer with units rounded to the given number of significant figures. 1) Find the voltage on a circuit with a resistance of 12.5 Ω if it has a current of 2.35 A. 2) If a circuit with a 9.

How do you best determine whether j/m2 and m*s2/n are equivalent units?

Which is the most important radiation conduction or convection? Explain

A compressed spring has 16.2 J of elastic potential energy when it is compressed 0.30 m. What is the spring constant of the spring?

A smart phone charger delivers charge to the phone, in the form of electrons, at rate of - 0.75 C/s. How many electrons are delivered to the phone during 45 min of charging?