1. In a chain reaction car accident on the North-South tollway, a BMW with a mas
ID: 1700497 • Letter: 1
Question
1. In a chain reaction car accident on the North-South tollway, a BMW with a mass of 2000 kg collides elastically with a Honda Civic (mass 1500 kg) at rest. The Honda in turn collides with a Hummer of mass 3000 kg in front of it, that’s also at rest, and the Honda and the Hummer lock bumpers and slide forward with a velocity of 3 m/s. (The BMW that originated the chain of events is not involved in the second collision). What was the velocity of the Honda right after the first collision and before it hits the Hummer?2. With regard to the BMW-Honda-Hummer collision problem, what was the velocity of the BMW right before the first collision?
3. With regard to the BMW-Honda-Hummer collision problem, what was the velocity of the BMW right after its collision with the Honda?
4. With regard to the BMW-Honda-Hummer collision problem, what is the net impulse on the "isolated system" during the first collision event?
5. A torque of 10 N m is applied to a 10 kg disk of radius 0.2 m initially at rest. What is the angular acceleration of the disk? Give your answer as a number expressed in units of rad/s2 but do not enter units into the answer box.
6. (With regard to the previous problem) The applied torque of 10 N m gets the disk rotating starting from rest. What is the angular velocity of the disk about an axis through its center, after it has completed two revolutions? Give your answer as a number expressed in units of rad/s but do not enter units into the answer box.
7. A figure skater spinning with an angular velocity of 20 rpm in the close position (arms, legs close to her axis of rotation) extends her arm and legs and increases her moment of inertia to 5 times her original value. As a result of this, the angular momentum of the skater:
a. increases by a factor of 5
b. decreases by a factor of 5
c. stays the same
d. cannot tell
8. A 5 kg bowling ball of radius 10 cm rolls on a level surface with a velocity of 5 m/s. What is the total kinetic energy of the ball? Give your answer as a number expressed in units of Joules but do not enter units into the answer box.
Explanation / Answer
5)
We know the formula for the torque acting on the disk is
T = I
= T / I
= T / (0.5mr^2)
= (10N.m)/[(0.5)(10kg)(0.2m)^2]
= 50 rad/s^2
(6)
Angular displacement of the disk is = 2 rev
= 2(2pi)rad
= 12.6 rad/s
Then final angular speed is
= sqrt(2)
= 35.4 rad/s
Please ask the remaining questions as separate.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.