Newton's First Law and motion

• Natuurkunde
• Middelbare school
• vwo
• Leerjaar 3

True or False, and explain;
When you stop cycling on your bycicle you slow down because there are no more forces.

Newton's First Law

"When the resulting force is equal to 0, an object moves with a constant speed or is standing stil

and vice verse. "

00:29

If the astronaut is 70 kg on Earth, then on the ISS:

1. Her mass is 70 kg and her weight is 0 kg.
2. Her mass is 70 kg and her weight is 0 N.
3. Her mass is 70 kg and her weight is 686 N.
4. Her mass is 0 kg and her weight is 0 N.

00:47

'Do you think that the laws of physics will hold up in the Space Station while experiencing micro-gravity?'

Yes

No

I do not know

01:15

Was Newton's first law confirmed by the astronaut's demonstration?

1. Yes
2. No
3. I do not know

01:39

Which type of friction or resistance does the hand that sticks out from a moving car experience?

1. Sliding resistance
2. Rolling resistance
3. Air resistance
4. All of the above

03:37

Can you use Newton's first Law to explain why the camera began moving without an astronaut putting a direct force on it?

phet.colorado.edu

Constant Speed

As long as the resulting force is equal to 0 then the speed will remain the same: 21,4 m/s

When you are cycling the muscle force is equal to the resistance. When this occurs the forces are in equilibrium.

Motion

Last year, you studied motion. 

Key concepts were distance, time and velocity.

There was some talk about acceleration.

You also learned this equation:      

v​ave​​=​t​​s​​

Acceleration

When there is a resulting force on an object the object will accelerate, decelerate or change direction. 

You can see that the velocity wil keep increasing as result when a person uses more muscle force. 

When he stops excerting this force only the friction remains and the object will slow down.

Distance

Velocity

Acceleration

meter

km/h

s

v

a

m/s

Mrs. Winkle drives 200 km in 4 hours. What is her average velocity?

1. 800 km/h
2. 200 km/h
3. 50 km/h
4. 4 km/h

Michael Phelps could swim with a maximal velocity of 2,7 m/s. What time would it take him to swim 50 m?

1. 135 seconds
2. 50 seconds
3. 18,5 seconds
4. 0,054 minutes

Marin is biking with a velocity of 6 km/h. She bikes for 10 minutes. What distance did she bike?

1. 6 km
2. 10 km
3. 60 km
4. 1 km

v,t - diagram

When, in this v,t-diagram, is there:

- uniform motion

- acceleration

- deceleration?

At t = 2 seconds, the resulting force is equal to:

1. 0 N
2. 3,5 N
3. 7 N
4. You can not know

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