Transcript A constant net force is applied to a person on

Slide1:
50 Newton is about equal to
1.
2.
3.
4.
5.
10 lbs
23 lbs
50 lbs
110 lbs
250 lbs
Slide 2
What is a net force?
1.
2.
3.
4.
A force acting on an object
All the forces acting downward
The combination of all the forces
When all the forces cancel out
Slide 3
You throw a rock in space. What is
required to keep the rock moving at
a constant velocity?
1. A constant force while its moving
2. A very small force once its moving
3. nothing
Slide 4
A book is resting on a table. Since the
book is not moving
1. There is not a force acting on it
2. The table is pushing up with a greater force
than gravity is pulling down with
3. Gravity is pulling down with a greater force
than the table is pushing up with
4. The net force on the book must be zero
Slide 5
A constant (and not zero) net
force is applied to a person on
rollerblades. The person will…
1.Move at a constant velocity
2.Continually change velocity
3.Move for a while at a constant velocity and
then change velocity
4.It depends on how big the frictional forces are
Slide 6
There is a zero net force acting on a
person on rollerblades. You could say
1. The person is not moving
2. The person is moving at a constant velocity
(not zero)
3. The person is accelerating
4. Not enough information to tell
Slide 7
A person on rollerblades is pushed
with a constant force of 10 N and
experiences an unknown force of
friction. If the person moves at a
constant velocity of 2 m/s, you could
say…
1.
2.
3.
4.
friction = 0 N
friction = 5 N
friction= 10 N
friction = 20 N
1.
2.
3.
4.
Slide 8
To change the velocity of an object,
you need
forces
unbalanced forces
inertia
nothing