Classwork
Circular Motion and Kinematics in motion in one dimension
Question 1: Choose the correct answer. (___________/ 5 marks)
1) A car travels a total distance of 40 m within 25 seconds to complete one turn around the
roundabout. What are the average speed and the average velocity of the car?
A. average speed is 1.6 m/s, average velocity is +1.6 m/s.
B. average speed is 1.6 m/s, average velocity is 0 m/s.
C. average speed is 0.625 m/s, average velocity is +0.625 m/s.
D. average speed is 0.625 m/s, average velocity is 0 m/s
2) A ball is attached to a string that is 1.5m long. It is spun so that it completes two full
rotations every second. What is the centripetal acceleration felt by the ball?
A. 14.8m/s2
B. 237 m/s2
C. 75.4 m/s2
D. 59.2 m/s2
3) The position of a particle moving along straight line is given by 𝑥(𝑡) = 12𝑡 2 − 2𝑡, such that;
x is in meter and t is in seconds. Where is the particle located at zero seconds?
A. The particle is located at the origin.
B. The particle is located at 𝑥 = +10𝑚.
C. The particle is located at 𝑥 = −2𝑚.
D. The particle is located at 𝑥 = −10𝑚.
4) A particle is moving in a uniform circular motion with a constant speed V along a circle of
radius “r”. The acceleration of the particle is
A. Zero
B.
𝑣2
𝑟
𝑣
C. 𝑟 2
D. 𝑁𝑜𝑛𝑒 𝑜𝑓 𝑡ℎ𝑒 𝑎𝑏𝑜𝑣𝑒
5) An object is travelling at 15 m/s; 10 seconds later, it slows down to 8 m/s. What is the object’s
average acceleration?
A. +0.7 𝑚/𝑠 2 .
B. −0.7 𝑚/𝑠 2 .
C. +2.3 𝑚/𝑠 2 .
D. −2.3 𝑚/𝑠 2 .
Question 2: Circular Motion: (_______________/ 6 marks)
A rotating that is 15.3mm long is spun with its axis through one end of the rod. The other end of
the rod has a constant speed of 2010 m/s
a. What is the centripetal acceleration of the end of the rod. Write the answer in scientific
notation
b. If you were to attach 2.5g object to the end of the rod, calculate the force would be needed
to hold it on the rod.
c. What is the period? Write it in scientific notation
d. If the radius is doubled how will the force change?
e. List 3 ways to increase the centripetal force.
i.
_____________________________
ii.
____________________________
iii.
____________________________
Question 3: ( ____________/ 5 marks)
The position of an object as a function of time is given as x = At3 +Bt2 + Ct +D. The constants
are
A= 2.10 m/s2, B= 1.00 m/s2, C= -4.10 m/s and D =3.00 m
a. What is the velocity of the object at t =10s
b. At what time(s) is the object at rest
Hint: Use the calculator to solve the equation of power 2
c. What is the acceleration of the object at t=0.5s?
Question: 4: (____________/ 4marks)
An amusement ride is used to teach students about centripetal force. The ride is a circular wall
that you place your back on. The wall and floor then begin to spin. Once it reaches a certain
rotational velocity, the floor drops, and the students are pinned to the wall as a result
of centripetal force.
A student of mass 50kg decides to go on the ride. The coefficient of static friction between the
student and wall is 0.8. If the diameter of the ride is 10m,
a. Find the minimum force of friction needed to keep the student from falling.
b. Indicate the name of the centripetal force, and calculate its value.
c. Calculate the centripetal acceleration
d. Find the period of the ride rotation.
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