PHY 201 - Exam 2
3. test problem #3, look at paper
(2.0m, 1.9m)
10. A block with a mass of 1kg is traveling at a speed of 6m/s when it runs into the back of a second block with a mass of 7kg that is traveling at 2m/s. Both blocks are traveling in the same direction before the collision. Assuming that the collision is elastic, find the velocity of the two blocks after the collision.
-1 m/s, 3 m/s
a 100kg pendulum is hanging 12 m from a ceiling on a steel wire. A = 1 x 10^-5 m2 E = 2 x 10^11 N/m^2 how long will the steal wire stretch
.00588 m
FREE FALL Ks = 100N/m mass = 5 kg What is the distance it moves in the y direction spring problem
.49 meters
a 3 kg block sliding at 8 m/s to the right on a HES collides head on with a 6kg block sliding at 4 m/s to the left. If they stick together, how fast will they be moving after the collision
0 m/s
a pottery wheel at rest begins rotating with an angular acceleration of 8 RAD/s^2 1. how fast is it rotating @ 3s 2. how far is it at 3s 3. if break is applied at 3s and wheel turn through 3 revolutions, how long does it take to stop
1. 24 RAD/s 2. 36 RAD 3. a = -15.3 RAD/s^2 t = 1.57s
12. A 5kg block is sliding without friction at a speed of 7m/s. It then slides down a 3m tall hill and collides with a spring with a spring constant of 400N/m as shown in the figure. What is the maximum compression of the spring?
1.16 m
a child with a mass of 40kg is sitting 2m away from the center of a seesaw. the seesaw itself is 40m long and has a mass of 10kg. where should a 50kg child sit
1.6m away
an ideal spring with a constant of 3000 N/m is attached at the bottom of a rough inclined plane that makes an angle of 37 degrees with the horizontal. The spring is compressed a distance of 80 cm and then a 12kg box is placed on the spring as shown in the figure. The coefficient of kinetic friction between the box and the inclined plane is 0.2. If the box is released from rest and is not attached to the spring, how fast will the box be traveling after sliding 4m on the incline (3.2m beyond the uncompressed length of the spring)?
10 m/s
11. A solid cylindrical pulley with a mass of 4.0kg and a radius of 20cm is attached to a frictionless axle through its center as shown. A string is wrapped tightly around its circumference and then one end of the string is attached to a 5.0kg mass that is hanging in the air. If the 5.0kg mass is released from rest and the string does not slip on the pulley, what is the speed of the 5.0kg mass after the pulley has rotated through 6.0 revolutions?
10.3 m/s
a 3 kg mass is compressed 2m against a spring with a spring constant of 40 N/m. it is released from rest on top of a 7m tall hill and encountered a frictionless force of 11N over 5m on the way down. How fast is it moving at the bottom.
12.4 m/s
give 2 blocks together, what is their cm 6kg top right (20,12) bottom right (20,4) top left (16,12) 10 kg bottom right (20,0) bottom left (0,0)
13, 4.25
4. A 5kg block slides a distance of 4m down a rough inclined plane as shown in the figure. The inclined plane makes an angle = 30 with respect to the horizontal. If the block has an initial velocity of 2m/s down the inclined plane and a final velocity of 6m/s down the inclined plane, how much energy was lost by the block due to the work done by friction?
18J
pushing on a rectangular box on a HES, how much torque F = 7N box horiz = 40 cm box vertical = 30 cm p is at top right corner force is applied at bottom left
2.1 Nm
5. A 2.0kg mass is attached to the end of a 2.0m string. The mass is whirled in a horizontal circular path while on top of a frictionless surface. If the maximum tension the string can withstand before breaking is 400N, what is the maximum speed of the mass without breaking the string?
20 m/s
a spring is compressed 1.8m spring constant = 71 N/m mass = 5.8 kg v = 23.2 m/s how tall is the top of the hill
25.44 m
how much torque horizontal = 1 m angle of force = 30 degrees force = 30 N
25.98 Nm
a constant 7N horizontal force acts for 4s on a 5kg mass. what impulse was delivered
28 Ns to the right
find the CM of this system of 3 particles 10kg @ (0,3) 12kg @ (5,3) 20kg @ (5,0)
3.81, 1.57
8. A dumbbell is sliding across a frictionless table while rotating. The dumbbell consists of two 3kg masses separated by a massless bar of length 2m as shown in the figure. If the center of mass of the dumbbell has a speed of 3m/s and the dumbbell is rotating at 1rad/s, what is the dumbbell's total kinetic energy?
30 J
7. Two forces are applied tangentially to the edge of a disk of mass 8kg and radius 1m, as shown in the figure. What is the magnitude of the net torque on the disk if F1 is 70N and F2 is 40N?
30 Nm
2. A 3kg block is sliding at 8m/s on top of a frictionless horizontal surface. It then collides with a 2kg block at rest and sticks to the 2kg block. What is the speed of the two blocks after the collision?
4.8 m/s
6. A clockwise torque of 14Nm is applied to the edge of a rotating sphere with a mass of 70kg and a radius of 50cm initially spinning at a rate of 8rad/s counterclockwise. For how long must this torque be applied to bring the sphere to rest?
4s
2 m long string with a mass of 1kg in the middle and 1 kg at the end. what is the moment of inertia
5 kgm^2
a 10kg block is moving at 7m/s to the right on a HES when explodes into 2 pieces, one piece has a mass of 4kg and cont. to the right at 19 m/s. what does the other piece do?
6 kg -1 m/s
a real pulley with a mass of 4 kg and a diameter of 60 cm connected to a hanging 7kg mass by a string is wrapped many times around the pulley so it does not slip. What is the angular acceleration
7.62 m/s^2
1. In which of the following types of collisions is kinetic energy conserved? A) an elastic collision B) an inelastic collision C) a perfectly inelastic collision D) all of the above E) none of the above
A
9. A platform of mass 4kg and length 6m is attached to 2 supports as shown in the figure. The first support is at the left end and the second support is 2m from the left end. If a 1kg box is placed 4m from the left end, what is the force exerted by two supports on the diving board?
FA =29.4 N down FB = 78.4 N up
a diver with a mass of 50kg is standing on the edge of a 3m long, 10kg diving board. the supports are on the left end and 1m from the left end. find the force exerted on the diving board by supports A and B
FA= -1029N FB= 1617 N
a 3.0 m long beam with a mass of 20kg is used to hang a sign with a mass of 50kg. the beam is horizontal and attached at one end of the wall using a bolt and at the other end using a rope. the sign is hung from the beam at a distance of 50 cm away from the end of the beam. 22 degrees a. find the tension in the rope b. find the horizontal and vertical components of the force exerted on the beam by the bolt
FT = 1351.64 N FBolt,X = 1253.2 FBolt,Y = 180N
a 2m long board with a mass of 10kg is bolted on the left to a wall. a 20kg sign is hung from the right end and a rope is attached at 30 degrees to the right end to keep the board level. find the force of the rope, bolt in the x, and bolt in the y
FT= 490 N FBoltX = 424 N FBoltY= 49N
on a frictionless horizontal surface, a spring with a spring constant of 40 N/m is compressed 3m by a 5 kg mass. What is the potential energy
PE = 180 J
forces on a flat cylinder (disc) sitting on a HFS with a fixed pivot through its center m = 3kg r = 1/2m 10N applied at the top of the circle at 30 degrees from the axis 7N applied at the direct bottom of the circle (look at notes if you need a picture) what is the Torque, moment of inertia, and angular acceleration
T = 1 Nm I = .375 kgm^2 a = 8/3 RAD/s^2
13. A sign is hung out from the front of a building using a wooden beam and a cable as shown in the figure. The wooden beam is 4m long and has a mass of 3kg. The sign is attached a distance of 4m from the wall and has a mass of 7.5kg. The cable is attached to the wooden beam a distance of 3m from the wall and makes an angle of 37 degrees with the wooden beam. What is the tension in the cable? What are the horizontal and vertical components of the force exerted by the wall on the wooden beam at the point where the wooden beam is attached to the wall?
Tension = 195 N Horizontal = 156 N Vertical = -15N
A metal beam with a mass of 20kg and a length of 6.0m is bolted to a support at a distance of 1.0m away from the right end as shown in the figure. A box with a mass of 50kg is attached to the far left end of the metal beam. A rope that makes an angle of 60 degrees with respect to the horizontal and 30 degrees with respect to the vertical is tied to the right end of the metal beam. a. What is the tension in the rope? b. What force is exerted on the metal beam by the support through the bolt?
Tension = 3280N Horizontal = 1640N Vertical = 3530N
a 4 kg block is sliding @ 3 m/s on a HES collides with a 6 kg block at rest, elastically what are the two final velocities
VB= 2.4 m/s VA= -0.6 m/s
how much work must be done on a 1200 kg car to take it from rest to 100 m/s in a distance of 500m
W = 6,000,000 J
how much work is done on a 7 kg box sliding at 8 m/s with an applied force of 100 N against a friction of 30N. it moves a distance of 10 m
Wnet = 700Nm
a 10 kg block is sliding to the right at 3.00 m/s on a horizontal, frictionless surface. It then has a head-on-collision with a 4.00 kg block that is sliding at 5.00 m/s to the left. Assuming the collision is elastic and lasts for 20.0ms, find: a. the velocity of the 10.0kg block after the collision b. the velocity of the 4.00 kg block after the collision c. the average force exerted on the 4.00 kg block by the 10.0 kg block
a. -1.57 m/s b. 6.43 m/s c. 2300 N
drop a ball from 1.5m above the ground after hitting the ground it bounces back up to 1.5m. what impulse was delivered to the ball by the ground. 2kg ball
impulse = 21.68 Ns
a 5N force is applied to a 2kg mass for 4.0s, going 3 m/s to the right, what is the objects final velocity and final momentum
v = 13 m/s P = 26 Ns
drop an object from a height of 3m, how fast is it going when it hits the ground
v = 7.67 m/s
if you release the spring from above compressed at 3m how fast is it the mass moving when it is at the eq position?
v = 8.48 m/s
