Biomechanics exam 3

A ball is projected towards the ground at some angle. If there are frictional forces present and backspin is placed on the ball, what would happen to the angle of rebound if the coefficient of restitution is greater than one? The angle of rebound would A. increase B. decrease C. remain the same D. insufficient information to determine the angle of rebound E. there would not be an angle of rebound

B. decrease

Ball A with a mass of 8 kg moving 5 m/s east collides ball B (a 2 kg ball moving 10 m/s west). If the coefficient of restitution was equal to.0, then after impact, the momentum of ball A would be ________________ and the momentum of ball B would be ______________: A. 40 kgm/s east; 20 kgm/s west B. 20 kgm/s west; 40 kgm/s east C. 20 kgm/s east; 20 kgm/s east D. 16 kgm/s east; 4 kgm/s east E. 0 kgm/s; 0 kgm/s

D. 16 kgm/s east; 4 kgm/s east

Ball A with a mass of 10 kg moving at 5 m/s east collides with ball B which has a mass of 20 kg moving at 2 m/s east. After the collision, if both balls stick together, what would be their resulting velocity? A. 0.33 m/s east B. 0.33 m/s west C. 4 m/s east D. 3 m/s east E. 2 m/s east

D. 3 m/s east

In a penalty kick, a soccer ball with a mass of 1.5 kg, leaves the kicker's foot with a velocity of 10 m/s. If the foot is in contact with the ball for 0.25 sec, what is the force on the ball? A. 3.75 N B. 6 N C. 15 N D. 60 N E. Insufficient information to determine

D. 60 N

When a ball is projected downwards towards the ground and the coefficient of restitution is determined to be -0.5, which of the following statements is true? A. the ball did not bounce (i.e., hit the ground and stopped) B. the ball went through the ground C.rebound height and dropped height was used in determining the coefficient of restitution D. ball velocity was used in determining the coefficient of restitution E.there was a calculation error because the coefficient of restitution cannot be less than 0.

D. ball velocity was used in determining the coefficient of restitution

Which of the following will NOT affect the horizontal component (after impact) of a ball projected downwards towards the ground at some angle? A. angle of projection B. spin C. coefficient of friction D. coefficient of restitution E. speed of projection

D. coefficient of restitution

Assume there are frictional forces present, and the coefficient of restitution is greater than one. What would happen to the horizontal and vertical vector component after impact of a ball projected downwards towards the ground at some angle? The horizontal vector component would _____ and the vertical vector component would _____ A. increase; decrease B. increase; increase C. decrease; decrease D. decrease; increase E. increase; remain the same

D. decrease; increase

Which of the following will have the smallest momentum? A. a 20 kg object moving at 30 m/s B. a 30 kg object moving 20 m/s C. a 40 N object moving 40 m/s D. a 50 N object moving 30 m/s E. a 60 lb object moving 20 m/s

D. a 50 N object moving 30 m/s

A ball is projected towards the ground at some angle. If there are frictional forces present and backspin is placed on the ball, what would happen to the angle of rebound if the coefficient of restitution is less than one. The angle of rebound would A. increase B. decrease C. remain the same D. insufficient information to determine the angle of rebound E. there would not be an angle of rebound

D. insufficient information to determine the angle of rebound

Assume there are NO frictional forces present and the coefficient of restitution is greater than one. What would happen to the horizontal and vertical vector component after impact of a ball projected downwards towards the ground at some angle? The horizontal vector component would _____ and the vertical vector component would _____ A. increase; decrease B. remain the same; remain the same C. remain the same; decrease D. remain the same; increase E. none of the above

D. remain the same; increase

During a force phase a 500 N force is applied to a 100 kg object for 2.5 sec. If the initial velocity (Vi) of the object is 15 m/s during the force phase, what is the final velocity (Vf) for the object during the force phase? A. 0 m/s B. 5 m/s C. 12.5 m/s D. 15 m/s E. 27.5 m/s

E. 27.5 m/s

Which of the following statements is FALSE? It is possible for three different balls (i.e., racquetball, golf ball, squash ball) dropped from __________ to have _____________coefficient of restitution(s) A. the same height; different B. different heights; different C. different heights; the same D. the same height; the same E. none of the above (all of the above is true)

E. none of the above (all of the above is true)

Which of the following best describes the values of the coefficient of restitution for a ball dropped on to the ground? a 0 < e < 1 b 0 ≤ e < 1 c 0 ≤ e ≤ 1 d 0 > e > 1 e 0 ≥ e ≥ 1

b 0 ≤ e < 1

What is the coefficient of restitution of a ball dropped from a height of 100 cm and bounces up 25 cm? a 0.25 b 0.50 c 0.75 d 2.00 e 4.00

b 0.50

If ball A with a mass of 5 kg is moving 10 m/s east, collides with ball B (a stationary 5 kg ball). If ball A continues to move forward at 5 m/s, what is the momentum and velocity of ball B? a 50 kg.m/s east; 10 m/s east b 25 kg.m/s east; 5 m/s east c 50 kg.m/s west; 10 m/s west d 25 kg.m/s west; 5 m/s west e 25 kg.m/s east; 5 m/s west

b 25 kg.m/s east; 5 m/s east

Ball A with a mass of 5 kg moving 10 m/s east, collides with ball B (a 10 kg ball moving at 2 m/s west). If both balls stick together after the collision, what is their momentum and velocity? a 30 kg.m/s west; 2 m/s west b 30 kg.m/s east; 2 m/s east c 2 kg.m/s east; 30 m/s east d 2 kg.m/s west; 30 m/s west

b 30 kg.m/s east; 2 m/s east

The impulse-momentum relationship is based on which of Newton's Laws? a First Law b Second Law c Third Law d Fourth Law e Law of Gravitation

b Second Law

Based on the application of impulse-momentum to impart some given momentum to an object for maximum control, the force should be ___________, and the time of application ____________. a increased; decreased b decreased, increased c increased, remain the same d remain the same, decreased e increased, increased

b decreased, increased

Momentum is defined as the property of an object to resist a change in its motion as a function of its ... a mass and acceleration b mass and velocity c weight and acceleration d weight and velocity e none of the above

b mass and velocity

The coefficient of restitution acts _____________ to the surfaces in contact a parallel b perpendicular c at a 45 degree angle d a and b e all of the above

b perpendicular

Sort the momentum for each of the moving objects, from the smallest to the largest.

bullet running back car tank oil tanker

If ball A with a mass of 5 kg is moving 10 m/s east, collides with ball B (a stationary 5 kg ball). If ball A continues to move forward at 2 m/s, what is the momentum and velocity of ball B? a 40 kg.m/s west; 8 m/s east b 40 kg.m/s east; 8 m/s west c 40 kg.m/s east; 8 m/s east d 40 kg.m/s west; 8 m/s west

c 40 kg.m/s east; 8 m/s east

Ball A with a mass of 10 kg moving 5 m/s east, collides with ball B (a 15 kg ball moving at 2 m/s east). If both ball stick together, what is their resulting momentum and velocity? a 3.2 kg.m/s east; 80 m/s east b 3.2 kg.m/s west; 80 m/s west c 80 kg.m/s east; 3.2 m/s east d 80 kg.m/s west; 3.2 m/s west

c 80 kg.m/s east; 3.2 m/s east

The Law of Conservation of Linear Momentum can be used to predict velocity outcomes of head-on collisions ... a before the collision b during the collision c after the collision d a and b e all of the above

c after the collision

In the application of the impulse-momentum to jump up to 50% of the maximum height as quickly as possible, the force should be _________ and the time of application ____________. a increased, increased b increased, remains the same c increased, decreased d decreased, decreased e decreased, increased

c increased, decreased

Based on the application of impulse-momentum to stop the momentum of an object, if the applied force __________, the time of application ______________. a increases, also increases b increases, remains the same c increases, decreases d decreases, also decreases e decreases, remains the same

c increases, decreases

If ball A with a mass of 5 kg is moving 10 m/s east, collides with ball B (a stationary 5 kg ball). If ball A moves backwards at 2 m/s west, what is the momentum and velocity of ball B? a 60 kg.m/s west; 12 m/s west b 60 kg.m/s west; 12 m/s east c 60 kg.m/s east; 12 m/s west d 60 kg.m/s east; 12 m/s east

d 60 kg.m/s east; 12 m/s east

Head-on collisions between two objects or performers can only occur when both performers are ... a moving in opposite directions b moving the same direction c stationery d a and b e all of the above

d a and b

If an impulse is applied to change the momentum of an object, and the mass of the object is constant, the object's velocity can ... a increase b decrease c remain the same d a and b e all of the above

d a and b

The impulse-momentum equation describes how the momentum of an object can be changed by ... a changing the force acting on it b changing the time a force is applied to it c changing the weight of the object d a and b e all of the above

d a and b

Based on the application of impulse-momentum, an adult can throw a ball harder than a child because the adult can apply a __________ force to the ball for a _____________ period of time when compared to the child. a smaller, longer b smaller, shorter c larger, shorter d larger, longer e larger, same

d larger, longer

Which of the following will have the smallest momentum? a a 0.5 kg bullet moving at 100 m/s b a 882 N runner moving at 7 m/s c a 90 kg runner that covers a distance of 1610 m in 3 min and 50 seconds d a 9800 N piano that falls for 3 seconds e 1,000,000 kg oil tanker moving at 0 m/s

e 1,000,000 kg oil tanker moving at 0 m/s

Impulse can be described as ... a a force that can change the momentum of an object b equal to the product of a force and the time over which the force is applied c force x time d a and b e all of the above

e all of the above

Match the following to complete the equation

force = mass x acceleration momentum = mass x velocity impulse = force x time power = force x velocity

Match the application of impulse-momentum to the activity.

stopping the momentum of an object- catching a medicine ball imparting momentum for control- shuffle board imparting maximum momentum to an object- shot put shock absorbing impulse- landing from a jump

A ball that bounces up half-way to the height it was dropped from would have a coefficient of restitution equal to a 0.2 b 0.4 c 0.5 d 0.7 e 0.9

d 0.7

Determine the net momentum for the following systems before impact and then sort them from the smallest to the largest net momentum. Ball A with a momentum of ____________ collides with ball B with a momentum of ______________

50 kg.m/s east; 50 kg.m/s west 50 kg.m/s east; 30 kg.m/s west 25 kg.m/s west; 25 kg.m/s west 30 kg.m/s east; 50 kg.m/s east

Ball A with a mass of 3 kg moving 15 m/s east collides ball B (a 5 kg ball moving 6 m/s west). If the coefficient of restitution was equal to 1, then after impact, the velocity of ball A would be ________________ and the momentum of ball B would be ______________: A. 10 m/s west; 45 kg*m/s east B. 15 m/s west; 30 kg*m/s east C. 15 m/s east; 30 kg*m/s west D. 5 m/s east; 3 m/s west E. 5 m/s west; 3 m/s east

A. 10 m/s west; 45 kg*m/s east

Ball A with a mass of 10 kg moving 5 m/s east collides with ball B (a 15 kg ball moving 2 m/s west). What is the velocity of ball B if ball A moves backwards at 4 m/s? A. 4 m/s east B. 4 m/s west C. 60 m/s east D. 60 m/s west E. 20 m/s east

A. 4 m/s east

Ball A with a mass of 15 kg move 10 m/s east collides with ball B (a stationary 10 kg ball). After the collision, if both balls stick together, what is their resulting velocity? A. 6 m/s east B. 15 m/s west C. 15 m/s east D. 25 m/s west E. 150 m/s east

A. 6 m/s east

In the impulse-momentum equation, the Impulse part of the equation is mathematically defined by A. force x time B. mass x acceleration C. (Vf -Vi)/t D. mass x velocity E. force/time

A. force x time

The coefficient of restitution of a baseball can be increased by A. heating up the ball B. keeping the ball in a refrigerator C. keeping the ball at room temperature D. keeping the ball under low pressure E. keeping the ball in a vacuum

A. heating up the ball

A ball is projected towards the ground at some angle. If there are NO frictional forces present, and the coefficient of restitution is equal to zero, what would happen to the angle of rebound? The angle of rebound would A. increase B. decrease C. remain the same D. insufficient information to determine the angle of rebound E. there would not be an angle of rebound

A. increase

To maximize performance in shot putting, based on the impulse-momentum equation, the shot putter should attempt to apply a _________ force for a _______ period of time on the shot. A. large, long B. large, short C. small, long D. small, short E. large, moderate

A. large, long

Ball A with a mass of 10 kg moving at 5 m/s east collides with ball B (a 15 kg ball moving at 2 m/s west). After the collision, if both balls stick together, what is their momentum? A. 0.8 kg*m/s east B. 20 kg*m/s east C. 30 kg*m/s west D. 50 kg*m/s east E. 80 kg*m/s west

B. 20 kg*m/s east

What is the momentum of a 2940 N boulder that falls for 10 seconds? A. 2940 N B. 29400 kg*m/s C. 2940 kg D. 294 m/s E. 294 kg

B. 29400 kg*m/s F = ma, m = F/a= 2940 N / 9.8 m/s2 = 300 kgVf = Vi + at= 0 m/s + (-9.8 m/s2) (10 s)= - 98 m/sMom = mv= 300 kg x 98 m/s= 29400 kg*m/s

Ball A with a mass of 5 kg moving at 10 m/s east collides with ball B (a stationary 2 kg ball). What is the momentum of ball B if ball A moves forward at 2 m/s? A. 40 kg*m/s west B. 40 kg*m/s east C. 50 kg*m/s east D. 10 kg*m/s west E. 20 kg*m/s east

B. 40 kg*m/s east

If an 882 N runner has a momentum of 630 kg*m/s, what is the runner's velocity? A. 0.714 m/s B. 7 m/s C. 1.4 m/s D. 9.8 m/s E. 64 m/s

B. 7 m/s

A ball is projected towards the ground at some angle. If the coefficient of friction is equal to 1.0, and no spin is placed on the ball, what would happen to the angle of rebound if the coefficient of restitution is equal to 1.0? The angle of rebound would A. increase B. decrease C. remain the same D. insufficient information to determine the angle of rebound E. there would not be an angle of rebound

B. decrease

In catching a ball, if the time interval is increased, the force needed to stop the momentum of the ball will A. increase B. decrease C. remain the same D. increase or remain the same E. decrease or remain the same

B. decrease

When standing on a sheet of ice, which of the following jumping and landing strategies will most likely cause the ice to crack? Assume a person is jumping to 50% of his/her maximum height. Jumping with a ___________ force over a ___________ period of time, and landing with a _______________ force over a ___________ period of time. A. high, short; low, long B. high, short; high, short C. low, long; low, long D. low, long; high, short E. moderate, moderate; moderate, moderate

B. high, short; high, short

Assume that the coefficient of friction is equal to zero, and the coefficient of restitution is equal to one. What would happen to the horizontal and vertical vector component after impact of a ball projected parallel to the ground (at an angle of 0 degrees)? The horizontal vector component would _____ and the vertical vector component would _____ A. increase; decrease B. remain the same; remain the same C. remain the same; decrease D. remain the same; increase E. decrease; remains the same

B. remain the same; remain the same

Which of the following statements is true? When a ball is projected downwards towards the ground at some angle, upon contact with the ground and in a global reference system, the coefficient of restitution acts in the __________ axis, and friction forces act in the ___________ axis. A. +x, -y B. +x, +y C. +y, -x D. -y, -x E. +y, -y

C. +y, -x

Ball A with a mass of 10 kg moving at 5 m/s east collides with ball B (a 15 kg ball moving at 2 m/s east). After the collision, if ball A has a velocity of 4 m/s east, what is the momentum of ball B? A. 30 kg*m/s east B. 40 kg*m/s west C. 40 kg*m/s east D. 2.67 kg*m/s west E. 2.67 kg*m/s east

C. 40 kg*m/s east

If the coefficient of restitution is equal to 1, a tennis ball hit with topspin (where the ball is rotating slower than its motion forward), upon contacting the ground will have a _____ velocity and a ______ angle of rebound A. increased horizontal; increased B. increased vertical; increased C. decreased horizontal; decreased D. decreased horizontal; increased E. increased vertical; decreased

C. decreased horizontal; decreased

Which of the following statements is true? When a ball is projected downwards towards the ground at some angle, upon contact, the coefficient of restitution acts __________ to the 2 surfaces in contact, and frictional forces act ___________ to the 2 surfaces in contact. A. parallel, perpendicular B. parallel, parallel C. perpendicular, parallel D. perpendicular, perpendicular E. 45 degrees, 45 degrees

C. perpendicular, parallel

A ball is projected towards the ground at some angle. If the coefficient of friction is equal to 0, and no spin is placed on the ball, what would happen to the angle of rebound if the coefficient of restitution is equal to 1.0? The angle of rebound would A. increase B. decrease C. remain the same D. insufficient information to determine the angle of rebound E. there would not be an angle of rebound

C. remain the same

Which of the following statement(s) is TRUE? A. elasticity is a measurement of the coefficient of restitution B.elasticity is the measurement of the coefficient of restitution between two objects or surfaces during a collision C.elasticity is the property of an object to return to its' original shape once it has been deformed D.elasticity is the measurement of the coefficient of restitution between two objects or surfaces before a collision E.elasticity is measurement of the coefficient of restitution between two objects or surfaces after a collision

C.elasticity is the property of an object to return to its' original shape once it has been deformed

Two balls of equal masses rolls down the same ramp and hits a block of wood. When the first ball (A) hits the block, the ball stops and the block wobbles but does not tip over. When the second ball (B) rolls down the ramp and hits the block, the ball bounces backwards and the block wobbles and tips over. Which of the following statements is FALSE? A.Before impact with the block, the momentum of ball B was equal to that of ball A B.The coefficient of restitution of ball A with the block is less than that of ball B with the block C.After impact with the block, the momentum of ball A was less than that of ball B D.The momentum of the block after impact (when hit by ball B), was greater than the momentum of ball B before impact E.After impact, the momentum of the block when hit with ball A was equal to the momentum when hit with ball B

E.After impact, the momentum of the block when hit with ball A was equal to the momentum when hit with ball B

If ball A with a mass of 5 kg is moving 10 m/s east, collides with ball B, 5 kg ball moving 5 m/s west. If ball A stops, what is the momentum and velocity of ball B? a 25 kg.m/s east; 5 m/s east b 25 kg.m/s west; 5 m/s west c 50 kg.m/s west; 10 m/s west d 50 kg.m/s east; 10 m/s east

a 25 kg.m/s east; 5 m/s east

If ball A with a mass of 5 kg is moving 10 m/s east, collides with ball B (a stationary 5 kg ball). If ball A stops, what is the momentum and velocity of ball B? a 50 kg.m/s east; 10 m/s east b 50 kg.m/s west; 10 m/s west c 50 kg.m/s west; 10 m/s east d 50 kg.m/s east; 10 m/s west

a 50 kg.m/s east; 10 m/s east

For a ball dropped on to the ground, if the coefficient of restitution is equal to 0, it means the ball a did not bounce b bounces halfway up to the dropped height c bounces ¾ of the way up to the dropped height d bounces back up to the dropped height e bounces up higher than the dropped height

a did not bounce

What are the units for momentum? a kg*m/s b kg*m/s2 c kg*m2/s2 d kg2*m2/s2 e none of the above

a kg*m/s

Select ALL of the different applications of Impulse-momentum. a stopping the momentum of an object b changing the direction of a person in sport-related movements c imparting momentum to an object for control d imparting maximum momentum to an object e maintaining the momentum of an object

a stopping the momentum of an object b changing the direction of a person in sport-related movements c imparting momentum to an object for control d imparting maximum momentum to an object