Force/Motion Problems 8th Grade

0.5 kg Formula is P = MV So M = P/V So it is: 2kg m/s divided 4 m/s = .5 kg

A ball is rolling with a velocity of 4 m/s and has a momentum of 2 kg m/s. What is its mass? * 8 kg 8 N 2 kg 2 N 0.5 kg 0.5 N

6.525 kg m/s

A baseball has a mass of 0.145kg. The fastest pitch recorded had a velocity of 45m/s. How much momentum did the ball have? * 310.34 kg m/s 45.145 kg m/s 6.525 kg m/s 0.0032 kg m/s

Inertia

A car is traveling 60 miles per hour and hits a wall and comes to a complete stop. The driver does not have his seat belt on so flies forward at 60 miles per hour. Which of the following best explains why the driver is fling forward. There is only one correct answer. * Inertia Newton's Second Law of Motion F = m x a For every action there is an equal and opposite reaction Newton's Third Law of Motion

420 km Velocity = Distance/Time So.. Distance = Velocity x Time

A car travels for 6 hours at an average speed of 70 km/hr. How far did that car travel? * 0.086 hr 0.086 km 11.7 hr 11.7 km 420 hr 420 km

Motion

A change in position with respect to a reference point. * Force Work Energy Motion Power mass Momentum Weight

0.42 sec Velocity = Distance/Time So.. Distance = Velocity x Time Time = Distance/Velocity

A major league pitcher can throw a baseball 45m/s, how long does it take to reach the catcher who is 19 meters away? * 855 sec 2.4 sec 0.42 sec 0.24 sec 0.002 sec

Three times Formula is P = MV

A moving car has momentum. If it moves three times as fast, its momentum is ______ as much? * Half Twice Three times The same Moving car has no momentum so none of the above.

6m/s Velocity = Distance/Time

A runner runs for 10 seconds and travel a distance of 60 meters, what is her average speed? * 600 m/s 6m/s 0.167m/s 600N 6N 0.167N 600m/s^2 6m/s^2 0.167m/s^2

Both have the same momentum Because of... Newton's Third Law: For every action, there is an equal and opposite reaction.

After firing, which has more momentum? * Captionless Image Cannon ball Cannon Both have the same momentum Neither Cannon or ball have momentum There is not enough information to solve.

Velocity

Defined by having both speed and direction. * Force Normal Force Vectors Velocity Joules Work

Decrease the mass

How can you increase the acceleration of a car? * Increase the mass Decrease the force Decrease the mass Decrease the velocity

Velocity has speed and direction.

How does Velocity differ from speed? * Velocity is much faster than speed. Velocity also has magnitude of speed. Velocity has speed and direction. Velocity also has time of speed. Velocity also tells you how much speed.

29.4 m/s Gravity on earth = 9.8 m/s/s Multiply by 3 seconds = 29.4 m/s

How fast would an object be falling here on Earth if it fell for 3 seconds if there was no air resistance? * 9.8 m/s 29.4 m/s 3.26 m/s 3 m/s 6.8 m/s 62.5 m/s

V = distance/time Example: meters/second

How is velocity measured?

2.17 hr Velocity = Distance/Time So.. Distance = Velocity x Time Time = Distance/Velocity

How long does it take a marathon runner to complete the 26 mile race at an average speed of 12 mi/hr? * 0.46 hr 2.17 hr 3.14 hr 4.26 hr 312 hr

3 hours

How long will it take to travel 150 miles at a speed of 50 miles per hour? * 3 hours 10 hours 7 hours 1 hour 30 min 100 hours 6 hours 4 hours

12N

How much force is needed to accelerate a 6 kg ball at a rate of 2 m/s^2? * 3N 0.33N 12N 3kg 0.33kg 3kg

200N

How much force is required to accelerate a 100kg object 2m/s^2? * 0.02N 0.02kg 50N 50kg 200N 200kg

0 j Formula is Work = Force x Distance /Time But because it is against a wall it isn't moving, so distance = 0 800 N x 0 m /2 hours = 0 j

How much work is done pushing 800 N against a wall for 2 hrs? * 0 j 1600 j 400 j 0.0025 j 800 j 2 j 802 j

1.4 km/min Velocity = Distance/Time Total distance = 10 + 0 + 4 = 14 km Total time = 5 + 2 + 3 = 10 min 14km/10min = 1.4 km/min

If a car travels 10 km in 5 min, stops for 2 min, and then travels 4 km in 3 min, what is the average speed of the car for the total trip? * 14 km/h 14 km/min 1.4 km/min 1.4 km/h 15 km/h

5 m/s^2

If a car with a mass of 2,000kg can generate 10,000N of force, how fast will it accelerate? * 20,000,000 m/s^2 0.2 m/s^2 5 m/s^2 20,000,000 m/s 0.2 m/s 5 m/s

42 min

If there was a tunnel through the Earth, how long would it take to fall through the Earth to the other side? * 24 hr 365 days 42 min 18 sec 18 weeks

Terminal Velocity

In a falling object what is the term when the force of friction equals the force of gravity. * Normal Force Unbalanced Force Terminal Velocity Acceleration Deceleration

Fluid Friction

In the picture below of the "after" cannon is fired, what type of friction does the cannon ball experience? * Sliding Friction Rolling Friction Normal Friction Fluid Friction No Friction

Rolling Friction

In the picture below of the "after" cannon is fired, what type of friction does the cannon experience? * Sliding Friction Rolling Friction Normal Friction Fluid Friction No Friction

3 kg Formula is P = MV So Mass = P/V

The Momentum of the rocket (P1) is 150 kg m/s. If its velocity is 50 m/s, what is its mass? * 3 kg 0.33 kg 7500 kg 50 kg 150kg

150 kg m/s Because of... Newton's Third Law: For every action, there is an equal and opposite reaction. Also, remember Formula is P = MV

The Momentum of the rocket (P1) is 150 kg m/s. What is the momentum of the water (P2) leaving the the rocket? * 75 kg m/s 300 kg m/s 150 kg m/s 0 kg m/s 25 kg m/s 30 kg m/s

Mass

The amount of matter in an object. * Mass Weight Force Power Momentum Work Energy Motion

is speeding up.

The best description for the motion of a bicycle in the graph below is that the bicycle * is speeding up. is at rest. is slowing down. has a constant speed. is moving in the opposite direction.

The cannon has a force equal to the cannonball. Newton's Third Law: For every action, there is an equal and opposite reaction. Formula is Force = Mass x Acceleration Cannon = 100 Cannon Ball = 1 The cannon ball has more acceleration than the cannon because the cannon is heavier (i.e. has more mass)

The cannon is 100 times the mass of the cannonball. If the cannonball is shot to the right with some force, what is the force of the cannon to the left? * -The cannon has a force 100 times more than the cannonball. -The cannon has a force 100 times less than the cannonball. -The cannon has a force equal to the cannonball. -There is no force felt by the cannon. -The cannon has twice the force of the cannonball. -The cannon has half the force of the cannonball.

1500 N Formula is Force = Mass x Acceleration

The cannonball has a mass of 10 kg. The blast of the gunpowder accelerates the cannonball at a rate of 150 m/s^2 in the barrel. What is the force experienced by the cannonball? * 1500 N 15 N 0.067 N 160 N 150 N 15000 N

Mass and Velocity

The momentum of an object depends on: * Mass and Velocity Force and Mass Velocity and Acceleration Acceleration and Velocity Velocity and Force

Mass and Velocity Formula: P = MV P = momentum

The momentum of an object depends on: * Mass and Velocity Force and Mass Velocity and Acceleration Acceleration and Velocity Velocity and Force

2 kg Formula is Force = Mass x Acceleration Mass = Force/Acceleration

The net force on an object is 10 N and its acceleration is 5 m/s^2. What is its mass? * 50 kg 2 kg 5 kg 15 kg 0.5 kg 1.5 kg

Inertia = Newton's First Law of Motion

The resistance of an object to any change in motion. * Newton's Second Law of Motion Inertia Newton Joules Newton's Third Law of Motion

The woman and cart would move to the right about half the distance as the ball went to the left.

The woman in the picture below sitting on a cart with wheels has a medicine ball half her weight. If she tosses the object to the left, what would happen to the woman and the cart? * Nothing, they would not move. -The woman and cart would also move to the left about the same distance as the ball. -The woman and cart would move to the right about the same distance as the ball went to the left. -The woman and cart would also move to the left about half the distance as the ball. -The woman and cart would move to the right about half the distance as the ball went to the left.

Power

Watts is a unit of: * Energy Work Power Force Distance Momentum

4 m

What distance would a 25 N object be lifted if 100 j of work was done? * 0.25 m 4 m 2500 m 125 m 25 m 100 m

Both of the above

What does the force of friction depend on? * Type of surface How hard the surfaces are pushed together None of the above Both of the above

Increases

What happens to your momentum as you speed up? * Stays the same. Decreases. Increases. Speed does not effect momentum.

The object will fall at a constant speed

What happens when the downward force of gravity is equal to the air resistance of a falling object? * The object will stop falling. The object will fall faster The object will slow down The object will fall at a constant speed

Newton's First Law states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force. = inertia

What is Newton's First Law?

Force = Mass x Acceleration

What is Newton's Second Law?

For every action, there is an equal and opposite reaction. Ex. When you are standing, gravity pushes you down and the earth pushes you up

What is Newton's Third Law?

2 m/s^2 Formula is Force = Mass x Acceleration Acceleration = Force/Mass

What is the acceleration of a train that is traveling North at a speed of 10 m/s, that speeds up to 16 m/s in 3 seconds? * 16 m/s^2 8 m/s^2 2.5 m/s^2 2 m/s^2 1m/s^2

Mass is the actual amount of material contained in a body and is measured in kg, gm, etc. Weight depends on the gravity where you are. Ex the earth and the moon.

What is the difference between mass and weight?

work / time

What is the formula for Power? * force x distance force / distance work x time work / time force x mass force / mass force x time force / time

Acceleration = Force/Mass

What is the formula for acceleration?

Mass = Momentum divided Velocity M = P/V

What is the formula for mass (if you know velocity)?

P = MV P = momentum

What is the formula for momentum?

V = P/M

What is the formula for velocity? Remember P = MV

W = M x G G is gravity

What is the formula for weight?

100 kg Formula is F = MA M = F/A So... 200N/ 2m/s^2 = 100 kg

What is the mass of an object that requires 200 N of force to accelerate it 2 m/s^2 * 400 kg 100 kg 200 kg 0.01 kg 50 kg

15Kg Formula is Force = Mass x Acceleration Mass = Force/Acceleration

What is the mass of an object that requires 300N of force to accelerate it 20m/s^2? * 6000kg 6000N 15Kg 15N 0.667kg 0.667N

Newtons = force that would give a mass of one kilogram an acceleration of one meter per second per second,

What is the measure of weight?

3 kg m/s Formula is: P = MV So: .02KG x 150m/s

What is the momentum of the bullet leaving the gun? * 3 m/s 3 kg m/s 7500 kg m/s 7500 m/s 303 m/s 303 kg m/s None of the above

3 kg m/s Because of... Newton's Third Law: For every action, there is an equal and opposite reaction. And you know that the bullet is 3 kg m/s

What is the momentum of the gun (recoil) after firing? * 3 m/s 3 kg m/s 7500 m/s 7500 kg m/s 303 m/s 303 kg m/s None of the above

3 kg m/s

What is the momentum of the two cars After the collision? * 0 kg m/s 3 kg m/s 2 kg m/s 0.67 kg m/s 1 kg m/s 9 kg m/s

40 m/s Formula: P = MV P = momentum

What is the speed (velocity) of a 10kg object with a momentum of 400kg m/s? * 4000 m/s 400 m/s 40 m/s 4 m/s 0.025 m/s

0.5 m/s Formula is Velocity = Distance/Time = 5 meters/10 seconds

What is the speed of train A? * 0.5 m/s 1 m/s 5 m/s 10 m/s 2 m/s 15 m/s

1 m/s Formula: P =MV Car 1 = 3m/s x 1kg = 3 The mass of car 1 and 2 together = 3 So the velocity = the momentum (3) divided by the mass (3) = 1

What is the velocity after the collision? * 0 m/s 3 m/s 2 m/s 0.67 m/s 1 m/s 9 m/s

1.5 m/s Formula is P = MV V = P/M 3 (momentum) divided by 2KG = 1.5 m/s

What is the velocity of the gun (recoil) after firing? * 1.5 m/s 3 m/s 150 m/s 1.5 kg m/s 3 kg m/s 150 kg m/s

9.8 Newtons Because the gravity on earth is 9.8 m/s²

What is the weight of 1 KG on earth?

Fluid Friction.

What kind of friction slows a falling object like this skydiver? Sliding Friction. Static Friction. Fluid Friction. Rolling Friction. Normal Friction.

Constant Speed.

What motion is happening in this graph? * Speeding Up. Slowing Down. No Motion. Constant Speed. Constant speed in the opposite direction.

No Motion.

What motion is happening in this graph? * Speeding Up. Slowing Down. No Motion. Constant Speed. Constant speed in the opposite direction.

mass & momentum

What two variables are needed to calculate velocity? * distance & mass momentum & time mass & time distance & momentum mass & momentum acceleration and mass momentum and acceleration

Graph I Notice how distance goes to 0 Because he went home.

Which graph best illustrates the scenario: Tom went out for a walk with some friends. He suddenly realized he had left his wallet behind. He ran home to get it and then had to run to catch up with the others.

Bowling Ball = because it has the most mass and that means that it requires the most force to start or stop it.

Which has the most inertia * Feather Baseball Tennis Ball Bowling Ball Basket Ball

22 kg

Which is a mass? * 45 m/s 85 N 22 kg 150 m 2 kg m/s

Newtons (N)

Which is a unit of Force? * Kilograms (kg) Newtons (N) Meters per second square (m/s^2) Meters per second (m/s)

N = newtons

Which is a unit of Force? * kg N kg m/s m/s^2 m/s m

Meters per second square (m/s^2)

Which is a unit of acceleration? * Kilograms (kg) Newtons (N) Meters per second square (m/s^2) Meters per second (m/s)

Meters per second (m/s)

Which is a unit of velocity? * Newtons (N) Meters per second (m/s) Kilograms (Kg) Meters per second square (m/s^2) Kilogram meters per second (Kg m/s) Meters (m) Second (s)

mass x acceleration

Which is the formula for force? * mass x acceleration mass / acceleration mass x velocity mass / velocity acceleration / mass velocity / mass

Joules

Which is the unit of energy? * Newtons Watts Joules Kilogram meters per second Newtons per second

Two objects with the same mass will always have the same momentum.

Which of the following is NOT true? * -Momentum can be transferred. -When an object speeds up, it gains momentum. -The momentum of an object can change. -Two objects with the same mass will always have the same momentum. -All moving objects have momentum.

kilograms meters per second (kg m/s)

Which of the following is a unit of momentum? * meters per second (m/s) kilograms (kg) newtons (N) kilograms meters per second (kg m/s) meters per second square (m/s^2) meters

Carrying the book across the room.

Which of the following is an example of NO work being done to the book? * Picking up the book off the ground. Pushing the book across the table. Carrying the book across the room. Carrying the book up the stairs.

Matt Formula is Velocity = Distance/Time You need to calculate all of them and seeing which is bigger.

Which runner has the fastest average speed? * Andres Keshia Matt Sandra They are all running with the same average speed.

Fluid Friction

Which type of friction is experienced by an object that is falling through the air. * Sliding Friction Rolling Friction Fluid Friction No Friction