Unit 4 Dynamics

What is Newton's 2nd Law?

• Every action has an equal and opposite reaction

• An object at rest stays at rest, an object in motion stays in motion.

• F = ma

• Friction

Tags

NGSS.HS-PS2-1

True or False. Acceleration of an object is directly proportional to the net force acting on it

• True

• False

Tags

NGSS.MS-PS2-2

Find how much force the man will need to exert to move the car.

• 5000 N

• 50 N

• 20,000 N

• 500 N

Answer explanation

F = ma

Fnet = 1000 kg (.05 m/s²)

Fnet = 50 N

Tags

NGSS.MS-PS2-2

If the man pushes with an equal amount of force, which object will accelerate more?

• Car because it has more mass

• Lawnmower because it has less mass

• Car because it has less mass

• Lawnmower because it has more mass

Tags

NGSS.MS-PS2-2

What unit do we measure force in?

• Kilometer/hr

• Joules

• Seconds

• Newtons

If an object was accelerating at 5 m/s², and a force of 10 newtons was required to accelerate it, what was the object's mass?

• 50 kg

• 2 kg

• 0.5 kg

• 5 kg

Answer explanation

F = ma

10 N = m ( 5 m/s²)

mass = 2 kg

Tags

NGSS.MS-PS2-2

An object with greater mass would require ___________ force to accelerate.

• less

• the same

• greater

• doesn't matter

Tags

NGSS.MS-PS2-2

If the person is pushing backwards with the paddle, why do they move forward?

• The person will actually move backwards, they need to paddle the other way

• The water pushes back with an equal and opposite force

• The person is pushing harder than the water

• The water pushes back with a greater force than the person

Tags

NGSS.MS-PS2-1

A book rests on a table. The force of gravity pulls down on the book with a force of 20N. What prevents the book from falling down into the ground?

• The table and the book are pushing back with an acceleration of 9.8m/s².

• The table pushes back up on the book with a force greater than 20N

• The inertia of the book is equal to the inertia of gravity

• The table pushes back up on the book with an equal and opposite force of 20N

Tags

NGSS.MS-PS2-2

When a heavy football player and a light one run into each other, who exerts more force

• The light one

• Their force are equal

• The heavy one

Tags

NGSS.MS-PS2-1