Calculating Net Force

1
Calculating Net Force
2
When calculating force, remember, force has
direction.
3
Braden pushes on a box to the right with a force
of 50 N, and Anthony pushes on the box to the
left with a force of 60 N.
a. Draw a picture showing the forces.
b. What is the net force on the box?
c. What will happen to the box?
b. Fnet10N Left
c. Box will move left.
4
Arielle is driving East and pushes down on the
gas pedal in her car and causes the engine to
give a force of 1000 N to the tires on the car.
Air and ground resistance push back on the car
to the West with a force of 850 N.
a. Draw a picture showing the forces.
b. What is the net force on the car?
c. What will happen to the car?
b. 150N to the East
c. The Car will speed up to the East.
5
A box is sliding down an icy hill at a constant
speed.
a. Draw a picture showing the forces.
b. What is the net force on the box?
c. What will happen to the box?
b. 0 N
c. The motion of the box will not change.
6
For the box in question 3, Mark pushes against
the box up hill with 40 N of force.
a. Draw a picture showing the forces.
b. What is the net force on the box?
c. What will happen to the box?
b. 40N up the hill
c. The motion of the box will continue down the
hill, however the force being applied by Mark
will slow down the box.
7
If Mark continues pushing this way for a longer
time, what will happen to the box?
The box will start going up the hill.
8
For the box in question 3, Sua pushes against the
box up hill with 40 N of force and Hilary pushes
the box downhill with 40 N of force.
a. Draw a picture showing the forces.
b. What is the net force on the box?
c. What will happen to the box?
b. 0 N
c. The box will not change its motion.
9
For the box in question 3, Mike pushes against
the box up hill with 40N of force and Arman
pushes the box downhill with 50N of force.
a. Draw a picture showing the forces.
b. What is the net force on the box?
c. What will happen to the box?
b. 10N Down Hill
c. The box will speed up down the hill
10
For the box in question 3, Sam pushes against the
box up hill with 40N of force and Natalia pushes
the box downhill with 30N of force.
a. Draw a picture showing the forces.
b. What is the net force on the box?
c. What will happen to the box?
b. 10N Uphill
c. First slow down, then starts going uphill
11
For the box in question 8, how hard (and in what
direction) would Sam need to push the box for the
box to continue sliding down the hill at a
constant speed.
a. Draw a picture showing the forces.
b. Reduce the force at which he is pushing by
10N.
12
For the situations in the following figures
calculate the net force on the box. Remember to
include direction!
a.
25N South
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b.
50N West
c.
4N Right
14
d.
20N Left
e.
20N West
15
f.
36N Down
Make up a question like question 1 and have your
neighbour answer it.