Download WORKSHEET – Dynamics 2 - Westgate Mennonite Collegiate

WORKSHEET – Dynamics 2
1.
A physics book sits at rest on a table. You give it a brief push, so that the book
starts to slide. It slides a short distance and then stops again.
a)
Why was it motionless before being pushed?
b)
Why did it move when it was pushed?
c)
Why did it come to a stop?
d)
Under what conditions would have kept moving? (List
several possibilities)
2.
The force of gravity is a mutual attraction between objects. A falling rock, for
example, is attracted to earth, and so accelerates towards it. Does the earth attract
to the falling rock?
3.
A cat has a mass of 4 kg. What would be its mass on the moon?
4.
When you are riding in a car, most people claim that they have the sensation of
being pushed backwards when the car speeds up, and being pushed forwards
when the car slows down. What is really going on?
5.
Complete this sentence: If there is no net force acting on an object, then its’
velocity must be __.
6.
If there is a net force acting on an object, then Newton’s second law says that it
must be accelerating. Why is it that my desk is not accelerating? There is a force
of gravity acting on it.
7.
While jumping on a trampoline, each time you make contact with the surface of
the trampoline there are forces acting between you and it. Describe the force that
each (you and the trampoline surface) experience, and the effect of these forces.
8.
A 10 kg briefcase is placed on a scale (which indicates forces in newtons). The
briefcase and scale are inside an elevator. What does the scale read while the
elevator is
a)
at rest
b)
accelerating upwards at 2 m/s2
c)
accelerating downwards at 2 m/s2
d)
moving upwards with constant velocity of 2 m/s
9.
An airplane has a mass of 3.1 × 104 kg, and the engine on takeoff provides an
applied force of 3.7 × 104 N [U]. Draw a free body diagram for the airplane, and
find its acceleration.
10.
Which of the four “fundamental” forces is responsible for the following:
a)
makes paint stick to the wall
b)
makes the moon go around the earth
c)
enables a car’s brakes to stop a car
d)
holds the nucleus together
e)
is linked to radioactivity
11.
A book has a mass of 2 kg on earth.
a)
What is the weight of the book on the earth?
b)
What is the mass of the book on the moon?
c)
What is the weight of the book on the moon knowing that
‘g’ on the moon is equal to 1.6 m/s2?
12.
Whiplash is a serious injury that can occur if you are in a car accident - especially
if you are hit from behind. Most people claim that your head is snapped
backwards in such an injury - what is the physics of what is really happening?
13.
Describe how Newton’s 3rd Law can be applied to the shooting of a gun.
14.
A car has a mass of 1200 kg. It accelerates at 3 m/s2 [E]. What is the net force
acting on the car?
15.
A bicycle is moving at 10 m/s. The rider locks up the tires and skids to a stop.
How long does it take to stop, if the coefficient of friction acting between the tires
and road is 0.3?
16.
While investigating a vehicle accident involving a truck hitting a parked car, the
forensics department of the police determine that the truck was moving at 10 m/s
on impact. There are also skid marks from the truck 30 m long leading to the
point of the collision. The coefficient of friction between the tires and the road is
determined to be 0.75. How fast was the truck going when the brakes were
slammed on? If the speed limit is 60 km/h ... was the truck speeding?
17.
A 75 kg person stands on a bathroom scale which measures forces in newtons.
The person and scale are inside of an elevator. What value does the scale read if
the elevator is
a)
not moving
b)
accelerating upwards at 3 m/s2
c)
accelerating downwards at 3 m/s2
d)
moving upwards with constant velocity of 3 m/s
18.
A 150 kg log has a rope tied to. The log is dragged at constant velocity of 1.5 m/s
by the rope which is horizontal. What is the tension in the rope?
19.
A 2.3 kg model rocket sits on its launch pad. What is the acceleration of the
rocket, if the rocket engine applies a force of 15 N upwards?
20.
How much force would the engine of the above problem need to supply in order
to accelerate the rocket upwards at 15 m/s2?
21.
A 65 kg swimmer steps off of a platform 10 m above the water. She drops down
to the water, and when she hits the water, she reaches 2 m below the surface
before coming to a stop.
a)
Find her velocity when she reaches the water surface
b)
Sketch a v-t graph for this motion
c)
How much force did the water exert on her while it brought
her to a stop? (assume it was constant)