Forces and Motion Flashcard

Front

Force of 20N: Acceleration of 5m/s²

Force of 54N: Acceleration of 13.5m/s²

Force of 100N: Acceleration of 25m/s²

What is the MASS of the car?

Back

4 kg

Answer explanation

They are all the same car.

M = F / A

So, divide any of the forces by the resulting acceleration.

M = 20 N / 5 m/s^2 = 4 kg

**remember a unit for mass is kg!!!

Front

Batman and Superman are pushing a train in opposite directions. Batman is pushing with a force of 120N, and Superman is pushing in the opposite direction with a force of 80N. What is the net force? And which way does the train move?

Back

Answer explanation

The net force is the total force acting on train. Superman's 80 N cancel out some of the force from Batman.

120 N - 80 N = 40 N <- net force on train

Because Batman is pushing away with more force, the train will move towards Superman.

Front

A car is pushed with a force of 70N, it accelerates at 40 m/s². What is the mass of the car?

Back

1.75 kg

Answer explanation

M = F / A

M = 70 N / 40 m/s^2

M = 1.75 kg

(the unit for mass is kg!)

Front

A 900 kg train accelerates from a speed of 70 m/s to 160 m/s in 2 minutes. Calculate force.

Back

675 N

Answer explanation

First find the acceleration by dividing the difference in velocity by the time in seconds. Then use the acceleration in the F=MA equation.

A = 160 m/s - 70 m/s =>
120 SECONDS

A = 90/120 = 0.75 m/s^2

F = M * A ....

F = 900 Kg x 0.75 m/s^2 = 675 N

...remember the unit for force is N!! (newtons)

Front

Which of the following is a unit of force?

Kilogram

,

Meter per second squared

,

Newton

,

Joule

Back

Newton

Answer explanation

Newtons (N) are a unit of FORCE.

Front

Which of the following is a unit for MASS?

Kg

,

N

,

cm

,

mL

Back

Kg

Answer explanation

KiloGrams are a unit of MASS.

Front

Two equal and opposite forces of 6.0 N act on an object. What is the unbalanced force on the object?

Back

0 N

Answer explanation

if the forces are equal, the net force is 0 N

Front

A 15kg object is subjected to a force that causes it to accelerate at 3 m/s². What is the magnitude of the force?

Back

45 N

Answer explanation

F = M * A

Front

A 10kg object is subjected to a force that causes it to accelerate at 6 m/s². What is the magnitude of the force?

Back

60 N

Answer explanation

F = M * A

Front

A 25kg object is pushed with a force of 100N. What is the acceleration of the object?

Back

4 m/s²

Answer explanation

A = F / M