Download BF WS 12b Quantitative FBDs with Vector Resolution

School of the Future
Physics I
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Date:
School of the Future
Physics I
Name:
Date:
BF WS 12b: Quantitative FBDs & Vector Resolution
BF WS 12b: Quantitative FBDs & Vector Resolution
Adapted from AMTA 2013 Modeling Instruction Materials (U4 Free Particle – WS3, V3.1)
Adapted from AMTA 2013 Modeling Instruction Materials (U4 Free Particle – WS3, V3.1)
Level II Problems:
8. A mother is pushing her baby in a stroller
(combined mass, 20 kg) at a constant
velocity. She applies a force of 7 N at an
angle of 30°.
a. Make a qualitative FBD for the baby
plus the stroller (as one object).
b. Determine the normal force and the
frictional force applied to the stroller.
30°
9. A box of 100 N is suspended from a string
on an incline. The incline is at 60° and the
box is not moving.
a. Make a qualitative FBD for the box.
b. Determine the normal force and
the force of tension.
Level II Problems:
8. A mother is pushing her baby in a stroller
(combined mass, 20 kg) at a constant
velocity. She applies a force of 7 N at an
angle of 30°.
a. Make a qualitative FBD for the baby
plus the stroller (as one object).
b. Determine the normal force and the
frictional force applied to the stroller.
30°
9. A box of 100 N is suspended from a string
on an incline. The incline is at 60° and the
box is not moving.
a. Make a qualitative FBD for the box.
b. Determine the normal force and
the force of tension.
Level III and IV Problems:
10. A tire swing (15kg) hangs from a tree on a rope that is 4m long
(this includes the length of the tire too). It normally sits at rest 1m
above the ground. During a particularly nasty storm, the tire
swing experiences extreme wind forces, causing it “hover” at an
unknown angle. A brazen student seeing an opportunity for an
exciting physics application rushes out and measures the new
height of the tire above the ground to be 1.25m.
a. How much tension is there in the rope at this time?
b. How much force does the wind apply to the tire swing?
Level III and IV Problems:
10. A tire swing (15kg) hangs from a tree on a rope that is 4m long
(this includes the length of the tire too). It normally sits at rest 1m
above the ground. During a particularly nasty storm, the tire
swing experiences extreme wind forces, causing it “hover” at an
unknown angle. A brazen student seeing an opportunity for an
exciting physics application rushes out and measures the new
height of the tire above the ground to be 1.25m.
a. How much tension is there in the rope at this time?
b. How much force does the wind apply to the tire swing?
11. A child of mass mC sits on a sled at the top of a snow-covered
hill. The hill is 20m high (vertically) above sea level. The child
slides down the slope at an average (nearly constant) velocity of
1.5m/s and reaches the bottom in 30s.
a. Determine the magnitude of the normal force and
frictional force that the child experiences during her slide
down the hill. (Assume friction from the ground and drag
from air to be one force.)
b. Assume the child traveled down the hill at an average
11. A child of mass mC sits on a sled at the top of a snow-covered
hill. The hill is 20m high (vertically) above sea level. The child
slides down the slope at an average (nearly constant) velocity of
1.5m/s and reaches the bottom in 30s.
a. Determine the magnitude of the normal force and
frictional force that the child experiences during her slide
down the hill. (Assume friction from the ground and drag
from air to be one force.)
b. Assume the child traveled down the hill at an average
speed of vS in time tTOTAL, starting at a height h. What is
the angle of the incline in terms of these constants?
speed of vS in time tTOTAL, starting at a height h. What is
the angle of the incline in terms of these constants?
NEVER DOUBT THAT A SMALL GROUP OF COMMITTED INDIVIDUALS CAN CHANGE THE WORLD, INDEED IT IS THE ONLY THING THAT EVER HAS. MEAD
NEVER DOUBT THAT A SMALL GROUP OF COMMITTED INDIVIDUALS CAN CHANGE THE WORLD, INDEED IT IS THE ONLY THING THAT EVER HAS. MEAD