Force and Motion

Which reference point could be used by a passenger in a car to show motion?

• the driver

• a stop sign

• your younger brothers car seat

• the acceleration pedal

Check all of the examples that would show an unbalanced force.

• a bird sitting on top of an elephant

• an evenly matched tug of war

• a bike rolling down a hill

• a student leaning back in their chair

• a student falling from leaning back in their chair

Which situation would knowing the velocity of an object be most important?

• a drag race

• shooting a basketball

• a 100 meter dash

Newton's 1st law of motion states . . .

• for every action there is an equal and opposite reaction

• the more mass an object has the more force needed to accelerate it

• an object will stay at rest/motion unless an unbalanced force acts on it

Newton's 2nd law of motion states . . .

• the force needed to move an object depends on how much mass the object has

• for every action force there is an equal reaction force

• objects will no move unless an outside unbalanced force causes them to move

Newton's 3rd law of motion states . . .

• an object moving at a constant velocity will continue unless acted upon by a nonzero net force

• if one object exerts a force on another object, the second object exerts a force equal in strength in the opposite direction of the first object

• the size and direction of a net force equals the mass times the acceleration

When you push on a door to open it, what is the reaction force?

• you

• the door opening

• the door pushing on you

• the person walking in the hall that you hit

Friction is affected by the type of ______ and how much _____ is applied to each object?

A girl pushes on a door to open it. Which 2 terms accurately describe the net fore acting on the door?

• contact and balanced

• contact and unbalanced

• noncontact and balanced

• noncontact and unbalanced

A bus driver drove from Gypsum to Salina. He drove the first 10 km in 10 minutes, the next 15 km in 8 minutes, and the final 12 km in 9 minutes. What was the drivers average speed for the trip?

 $Avg\ speed\ =\ total\ dist.\ \div\ time$  

• 1.8 km/m

• 132 mph

• 45 km/h

• 2.2 km/m