Practice Equilibrium

What three things does friction depend on?

A 10 kg box is pushed along a rough surface at a constant speed by a force of 300 N at an angle of 60 degrees below the horizontal. Find the kinetic coefficient of friction.

Mathematical Equivalence

ON

Complete the sum of the forces equations for the following scenario:

A box is pulled across a rough surface at a constant speed.

a

b

c

d

T

Tags

NGSS.MS-PS2-2

What do you know about an object in equilibrium?

Draw the free body diagram for a box being pulled along the ground at a constant speed.

Answer explanation

You should have:

Force of Gravity Down

Normal Force Up

(Fg=Fn in length)

Force applied OR tension one way left/right

Force of friction other direction

(Friction=Tension in length)

Tags

NGSS.MS-PS2-2

Describe a scenario where the normal force is greater than an object's weight.

What is the approximate weight of a 10 kg object?

• 10 N

• 1 N

• 100 N

• 1000 N

Tags

NGSS.HS-PS2-1

Describe a scenario where the normal force on an object is 0 N.

In a stoplight problem, the two ropes can have different tensions; yet, the ropes have the same horizontal (x) tension component as each other. How is this known?

• The angles of the ropes are equal

• The stoplight is in equilibrium, so the net horizontal force must be zero

• One rope is longer than the other

• Gravity acts only vertically, causing equal tensions

A 5.0 kg box rests on a ramp inclined at 15 degrees. A force of 20 N pulls up the ramp- what is the coefficient of friction?

Mathematical Equivalence

ON

Tags

NGSS.MS-PS2-2