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PHYSICS EOS FALL REVIEW 15-16
Marcus, Christine, Mary, and John performed three experiments to calculate the coefficient of static friction
between a car tire and the street. Their results are listed in the table below. The tire’s actual coefficient of static
friction as calculated by the tire company is 0.77.
Marcus
Mary
Christine
1.01
0.78
0.70
1.03
0.71
0.85
0.99
0.83
0.99
1. Which one of the students had the most precise calculations? Marcus
John
0.79
0.83
0.73
2. Which one of the students had the most accurate calculations? Mary
3. In your own words describe the difference between accuracy and precision. DO NO say that one is
“more correct” or “more accurate” than the other, that would be incorrect. Accuracy is how close a
measured value is to a true value. Precision is how close the measured values are to each other.
4. A runner is training for a marathon. During one of his training sessions he runs North for two hours and
covers a distance of 10 kilometers. He gets distracted by an ice cream stand and takes 15 minutes to
enjoy a cone. Once finished he decides to head home and takes 1.5 hours to run 5 kilometers South
where he stops at a Snuffer’s ending his training session with some cheese fries.
What was his average speed for the trip? 5.45 km/hr
5. Using the problem above, what was his displacement when he ended his training session? 5 km North
6. Patrice swims due North across a river at 3 m/s. The river flows Due East at 3 m/s. What is her resultant
velocity? Hint: Make a diagram. 4.24 m/s NE
7. Which of the following graphs above represents an object under constant acceleration? B
Which graph shows no acceleration acting on the object? D
Consider the graph below.
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8. Determine the average speed for the following times.
0-2 sec
4-6 sec
6-10 sec
5 m/s
0 m/s
5 m/s
10-12 sec
10 m/s
9. What is the total distance traveled by the vehicle from 0 to 3 seconds? 15 m/s
Consider the graph below.
10. What is the total distance traveled by the object between second 2 and second 5? 90 m
11. When does the object have a constant velocity? 2-5 s and 6-9 s
How can you tell? The slope of the curve is equal to the acceleration and the slope over these
intervals is 0.
12. When does the object have a positive acceleration? 0-2 s
What is the acceleration from time 1 to 2? 15 m/s2
What is the acceleration from time 6 to 9? 0 m/s2
13. An apple falls 3m straight down from its tree. What is the final speed of the apple right before it hits the
ground? 7.67 m/s
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14. A football player hits an opponent with a force of 150 Newtons. If the mass of the opponent is 100
kilograms and the opponent was not moving, find the acceleration of the player that was hit. Assume the
collision is perfectly elastic. 1.5 m/s2
15. Given the free body diagram above which vector best represents the weight on the cart? 2
Normal force? 3
16. If arrow 1 represents the applied force then which arrow would represent the friction force? 4
17. There are two types of friction, static and kinetic, determine the difference between the two. Static
friction is a force that must be overcome to move an object from rest. Kinetic friction is a force
that opposes a moving object.
18. A cannon shoots a projectile along a parabolic path, see diagram, and encounters no air resistance. At
point 2 what is the direction of the projectile’s acceleration, if any? The acceleration is straight down
because the only force acting on the object is gravity.
What direction does the net force point? The acceleration is straight down because the only force
acting on the object is gravity.
19. Max and Mina are attempting to move their refrigerator out of their kitchen. Max and Mina are not the
brightest of movers, thus Mina is pushing the fridge to the North with a force of 62N and Max is
pushing the fridge towards the South with a force of 108N. What is the magnitude and direction of the
net force on the refrigerator? 46 N South
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If the mass of the refrigerator is 300kg then how much acceleration do Max and Mina create on the
refrigerator? 0.153 m/s2
20. The Earth travels in a circular motion around the Sun. What direction would its velocity vector be if the
gravity between the Earth and the Sun suddenly ceased to exist? BE SPECIFC! Draw using a vector!
Straight down if the Earth is rotating clockwise.
21. On the figure above draw in the force acting on the object, the tangential velocity of the object and the
acceleration acting on the object. The centripetal force points toward the sun. The tangential
velocity points straight down if the Earth is rotating clockwise.
22. From the figure above: Object 2 is orbiting object 1 currently at a distance of 1x108 meters. Object 1’s
mass is 1x1020 kg and the mass of object two is 1x1010 kg. What is the force of gravity between them if
the gravitational constant is still 6.67x10-11 N.m2/kg2 ? 6670 N
23. Two objects attract each other with a force of gravity (Fgrav) of 36 N. If the distance separating the
objects is doubled and the masses one of the objects is tripled, then what is the new force of gravitational
attraction? 27 N
24. Two objects attract each other with a force of gravity (Fgrav) of 36 N. If the distance separating the
objects is increased by a factor of 4 and the masses of both objects are tripled, then what is the new force
of gravitational attraction? 20.25 N
25. A father takes his child to the park and wants to play on a seesaw with her. The child is sitting 2m from
the fulcrum and weighs 140N. How far on the other side must the father sit from the fulcrum in order to
balance the seesaw if his weight is 980N. 0.286 m
26. What is the momentum of a 6.0kg bowling ball if it is moving at 10 m/s? 600 kg m/s
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If this bowling ball hit another bowling ball with the same amount of mass and stops completely then
how much momentum does the second bowling ball have? 600 kg m/s
27. The impulse of a volleyball being hit by a volleyball player is equal to the change in momentum .
28. A car accelerated from zero to 10 m/s in 5s. If the mass of the car is 1,000 kg, what was the average
force required to accelerate it to its final velocity? 2000 N
29. An iron asteroid with a 100 kilogram mass is moving through the deep reaches of space at 10 m/s when
it collides with a stationary nickel asteroid of the same mass. The iron asteroid stops. What is the
momentum of the nickel asteroid after the elastic collision? 1000 kg m/s
30. On your way home from school you are driving at a prudent 10 m/s while secretly listening to Justin
Bieber. Unfortunately, a team of myopic international ninjas mistakes your 1976 Ford Pinto for an
Aston Martin owned by a British secret agent. They ram your car from behind applying a force of 200N.
It takes them 5 seconds to realize their mistake and hit the brakes to drive away. What is the resulting
change to your momentum? 1000 kg m/s