Physics question bank questions

Two vectors A and B have components Ax=4m Ay=3m and B= 3m and By=4m what is vector 4A-3B, respectively. What is the magnitude of the sum of the two vectors?

(7m)x+(8m)y

A battleship is moving forward at 20m/s. A cannonball is fired backwards from the ship at 100m/s relative to the ship. if the forward is positive, what is the velocity of a cannonball for an observer on a stationary ship next to the battleship?

-80m/s

A spring-loaded gun can launch projectiles at different angles with the same launch speed. At what angle should the projectile be launched in order to travel the greatest distance before landing?

45 Degrees

A certain vector has x and y components that are equal in magnitude. Which of the following is a possible angle for this vector in a standard x-y coordinate system

45 degrees because an angle of a vector is given by tan^-1=y/x tan^-1(1)= 45

How long would it take to travel 15cm, again use the correct number of sig figs. vel is 2.51

6.0s

You drive your dad's car too fast around a curve and the car starts to skid. What is the correct description of this situation?

Friction between the tires and the road is not strong enough to keep the cars in a circle

The graph of position vs time for a car is given below, what can you say about the velocity of the car over time (sharp rise then starts to curve down)

It slows down all the time

you throw a ball straight up into the air, after it leaves your hand, at what point in its flight does it have maximum value of acceleration

Its acceleration is constant because it is in free fall

The graph of position vs time for a car is given below, what can you say about the velocity of the car over time (straight postive line)

Its at constant velocity

What can you say about the acceleration of gravity acting on the stone and the feather?

Its equal and both always

you drive 4 miles at 30 miles per hour and another 4 miles at 50 miles per hour, what is your average speed for the whole 8 mile trip

Less that 40 mi/h because more time is spent at 30 miles per hour than at 50

You're on a Ferris wheel moving in a vertical circle. When the Ferris wheel is at rest, the normal force N exerted by your seat is equal to your weight mg. How does N change at the top of the Ferris wheel when you are in motion?

N is smaller than mg

A block of mass m rests on the floor of an elevator that is moving upward at constant speed. What is the relationship between the force due to gravity and the normal force on the block?

N=mg because the block is moving at constant speed so there is no net force

A block of mass m rests on the floor of an elevator that is accelerating upward. What is the relationship between the force due to gravity and the normal force on the block?

N>mg

You drop a package from a plane flying at constant speed in a straight line. Without air resistance, the package will:

Remain vertically under the plane while falling

If two vectors are given such that A + B = 0, what can you say about the magnitude and direction of vectors A and B?

Same magnitude but opposite direction

A mass m is placed on an inclined plane (µ > 0) and slides down the plane with constant speed. If a similar block (same µ) of mass 2m were placed on the same incline, it would

Slide down at constant speed because the force of gravity is doubled but friction is also doubled

You drop a rock off a bridge. When the rock has fallen 4 m, you drop a second rock. As the two rocks continue to fall, what happens to their seperation?

The separation increases as they fall

Given that A+B=C, and that |A|+|B|=|C|, how are vectors A and B oriented with respect to each other

They are parallel in the same direction

Given that A+B=C, and that |A|^2+|B|^2=|C|^2, how are vectors A and B oriented with respect to each other

They are perpendicular to each other (tight triangle)

A small car collides with a large truck. Which experiences the greater force?

They both experience the same

From the same height (and at the same time), one ball is dropped and another ball is fired horizontally. Which one will hit the ground first?

They will both hit at the same time

You and a friend can each pull with a force of 20 N. If you want to rip a rope in half, what is the best way to do so?

Tie a rope to a tree and both pull from the same end because then your force will be combined

Using dementional analysis, what does V^2/x equal

a

A ball is thrown straight upward with some inital speed. When it reaches the top of its flight (at height h) a second ball is thrown straight upward with the same inital speed. Where will the balls cross paths

above H/2 because the first ball has 0 inital speed while the second has large inital speed

A train travels 200 km between 2 cities, note that 1.0km=.621 mi. the distance in miles is

close to 120 miles

For a cannon on Earth, the cannonball would follow path b. If the same cannon were instead on the Moon, where g = 1.6 m/s2, which path would the cannonball take in the same situation

d

the train is traveling at a speed of 45 miles per hour, what is its speed in feet per second

equal to 66ft/s

What is the standard unit of mass?

kg

A skier goes over a small round hill with radius R. Because she is in circular motion, there has to be a centripetal force. At the top of the hill, what is Fc of the skier equal to?

mass of gravity- Normal force

If the average velocity is non-zero over some time interval, does this mean that instantaneous velocity is never zero at the same interval

no

If the position of a car is zero, does it speed have to be zero

no, speed does not depend on position, it depends on the change of position

Your little sister wants you to give her a ride on her sled. On level ground [with friction] , what is the easiest way to accomplish this?

pulling her from the front

Does the speedometer in the car measure velocity or speed?

speed

Two equal-mass rocks tied to strings are whirled in horizontal circles. The radius of circle 2 is twice that of circle 1. If the period of motion is the same for both rocks, what is the tension in string 2 compared to string 1?

t2=2T1

A box of weight 100 N is at rest on a floor where µs = 0.4. A rope is attached to the box and pulled horizontally with tension T = 30 N. Which way does the box move?

the box does not move because static friction is 40 compared to the tension of 30

During that sharp left turn, you found yourself pressing against the passenger door. What is the correct description of what is actually happening?

the door is exerting a leftward force on you

you drive for 30 min at 30 mi/hr and then another 30 min at 50 miles per hour, what is your average speed for the whole trip

Equal to 40 miles per hour

A small bug moves counterclockwise around the perimeter of a 30.0 cm diameter clock. The bug starts at 6 oclock and moves to 3 oclock in 10.0 seconds. What is the magnitude and direction V average for the bugs motion?

2.12 and positive 45

Which of the following vector is not scalar. 1. Wind is blowing N/NW at 20 mph 2.A temp of 90 Degrees farenheight 3.A mass of 200kg 4.A block moving 30 degrees above the floor

1 and 4 because vectors have magnitude and direction

A small bug moves counterclockwise around the perimeter of a 30.0 cm diameter clock. The bug starts at 6 oclock and moves to 3 oclock in 10.0 seconds. What is the vector V average for the bugs motion

1.5cm/s x +1.5cm/s y

A force F acts on mass M for a time interval T, giving it a final speed v. If the same force acted for the same time on a different mass 2M, what would be the final speed of the bigger mass?

1/2v

Two blocks of masses 2m and m are in contact on a horizontal frictionless surface. If a force F is applied to mass 2m, what is the force on mass m?

1/3 F becasue In order for mass m to accelerate at the same rate, the force on it must be smaller by a factor of 3, as the mass is 1/3 of the total.

Two tug-of-war opponents each pull with a force of 100 N on opposite ends of a rope. What is the tension in the rope?

100 N because it doesnt matter if a person or a tree is holding the other end of the rope

You tie a rope to a tree and pull on the rope with a force of 100 N. What is the tension in the rope?

100N

Which of the following is closest to an order of magnitude to a 35 year old professor in seconds

10^9

you throw a ball upward with an inital speed of 10m/s Assuming that there is no air resistance, what is the speed when it returns

10m/s

A tortise travels at 2.51 cm/s for 4.512 s which answer gives the total distance using the correct number of sig figs?

11.3 (3 sig figs)

Two vectors A and B are at right angles to each other. The magnitude of A is 12 units, and the magnitude of B is 5 units. What is the magnitude of vector A added vector B?

13 (look in notes)

Two vectors A and B are at right angles to each other. The magnitude of A is 12 units, and the magnitude of B is 5 units. What is the magnitude of vector A minus vector B?

13 (notes)

A force F acts on mass m1 giving acceleration a1. The same force acts on a different mass m2 giving acceleration a2 = 2a1. If m1 and m2 are glued together and the same force F acts on this combination, what is the resulting acceleration?

2/3a. Mass m2 must be (𝟏/𝟐m1) because its acceleration was 2a1 with the same force. Adding the two masses together gives (𝟑/𝟐)m1, leading to an acceleration of (𝟐/𝟑)a1 for the same applied force.

From rest, you step on the gas of your Ferrari, providing a force F for 4 seconds. During this time, the car moves 50 m. If the same force were applied for 8 secs, how much would the car have traveled during this time?

200m because t^2= Distace 4x

You step on the brakes of your Ferrari, providing a force F for 4 seconds. During this time, the car moves 25 m but does not stop. If the same force were applied for 8 seconds, how far would the car travel during this time?

25m<x<50m

write out .0038 g in kg using scientific notation with the correct sig figs

3.8x 10^-6

You are adding vectors of lengths of 20 and 40 units. What is the only possible resultant magnitude that you can obtain out of the following choices. 0,18,37,64,100

37

Using the common prefixes what is the equivilalent of .0038g

3800 micrograms

From rest, you step on the gas of your Ferrari, providing a force F for 40 m, speeding it up to a final speed of 50 km/hr. If the same force were applied for 80 m, what final speed would the car reach?

70 km/hr. the acceleration acts over a distance x = 40 m, to give a final speed of v2 = 2ax (why is there no v02 term?). In the second case, the distance is doubled, so the speed increases by a factor of .

A rider in a "barrel of fun" finds herself stuck with her back to the wall. Which diagram correctly shows the forces acting on her?

A

In outer space, gravitational forces exerted by a bowling ball and a Ping-Pong ball on each other are equal and opposite. How do their accelerations compare?

Accelerations are opposite, but larger for the ping pong ball

Which of the punts have the longest hang time

All have the same

In the game of tetherball, the struck ball whirls around a pole. In what direction does the net force on the ball point?

Along the horizontal component of the tension force

A projectile is launched from the ground at an angle of 30º. At what point in its trajectory does this projectile have the least speed?

At the highest point in the flight

A battleship simultaneously fires two shells at two enemy submarines. The shells are launched with the same initial velocity. If the shells follow the trajectories shown, which submarine gets hit first?

B gets hit first because A has more height

Which of the following is correct? A. If an equation is dimensional correcrt, it must be true and if not dimensional correct, it may be true. B. If an equation is dimensionally correct, it could be true, if it is not demensionally correct, it cannot be true

B. If an equation is dimensionally correct, it could be true. If an equation is not dimensionally correct, it cannot be true

You drop a rock off a bridge. When the rock has fallen 4 m, you drop a second rock. As the two rocks continue to fall, what happens to their velocities?

Both increase at the same rate

Below, you see two cases: a physics student pulling or pushing a sled with a force F that is applied at an angle θ. In which case is the normal force greater?

Case 1 because F is pushing down on the ground

In which case does block m experience a larger acceleration? In case (1), there is a 10 kg mass hanging from a rope and falling. In case (2), a hand is providing a constant downward force of 98 N. Assume massless ropes.

Case 2 because the tension is 98 due to the hand , in case one the tension is less than 98 because it is acceleration down

If you push with force F on either the heavy box (m1) or the light box (m2), in which of the two cases below is the contact force between the two boxes larger?

Case A because it needs more contact force to have the same acceleration

Consider two identical blocks, one resting on a flat surface and the other resting on an incline. For which case is the normal force greater?

Case A because we know that N = W. In case B, due to the angle of the incline, N < W. In fact, we can see that N = W cos(θ).

A box sits on an incline. As you increase the angle of the incline, the box will eventually begin to slide down. Why?

Components of the gravity force parallel to the plane increases and the normal force exerted by the board decreases

Consider the line labeld B in the v vs t plot, how does speed change for time a (consistant negative line)

Decreases, then increases in the negative meaning it switched directions

Does the odometer of a car measure distance or displacement

Distance

You swing a ball at the end of string in a vertical circle. Because the ball is in circular motion, there has to be a centripetal force. At the top of the ball's path, what is Fc equal to?

Fc=T+mg

What can you say about the force of gravity Fg acting on a stone and a feather?

Fg (weight) is greater in the stone because Fg is mass

Consider the line labeld A in the v vs t plot, how does speed change for time a (straight positive line)

Increases

If each component of a vector is doubled, what happens to the angle of that vector?

It does not change

The same small cart is now rolling down an inclined track and accelerating. It fires a ball straight [up] out of the cannon as it moves. After it is fired, what happens to the ball?

It falls back into the cart

Now the cart is being pulled along a horizontal track by an external force (a weight hanging over the table edge) and accelerating. It fires a ball straight out of the cannon as it moves. After it is fired, what happens to the ball?

It falls behind the cart

A smart car is rolling at constant velocity on a flat track. It fires a ball straight up into the air as it moves. After it is fired, what happens to the ball

It falls right back into the cart

Alice and bill are at the top of a building. Alice throws her ball downward. Bill simply drops his ball. Which has the greater acceleration right after its release

Neither, since gravity is acting only after the release they both have the same

does displacement of an object depend on the specific location of the origin of the coordinate system?

No because displacement is the difference between 2 coordinates

A box sits in a pickup truck on a frictionless truck bed. When the truck accelerates forward, the box slides off the back of the truck because

No net force acted on the box

A Ping-Pong ball is shot into a circular tube that is lying flat (horizontal) on a tabletop. When the Ping-Pong ball leaves the track, which path will it follow?

Straight line becasue there is no longer a force keeping it in a circle (think of bullet in a barrell)

Three blocks of mass 3m, 2m, and m are connected by strings and pulled with constant acceleration a. What is the relationship between the tension in each of the strings?

T1>t2>t3 becuase t1 is pulling the first set of blocks

A object falls from the tower of a battleship, the object moves straight and to the right onto the deck of the battleship. where will the object land on the battleship

The bottom of the tower bc of battleship movement

In the collision between the car and the truck, which has greater acceleration

The car

What is the standard unit of a meter?

The distance traveled by light in a vacuum in 1/299,792,458 of a second

In the previous problem, which ball has the greater velocity at ground level?

The fired ball because it started with more horizontal velocity

In outer space, a bowling ball and a Ping-Pong ball attract each other due to gravitational forces. How do the magnitudes of these attractive forces compare?

The forces are equal and opposite

When you climb up a rope, the first thing you do is pull down on the rope. How do you manage to go up the rope by doing that?

The rope actually pulls you up

An astronaut on Earth kicks a bowling ball and hurts his foot. A year later, the same astronaut kicks a bowling ball on the Moon with the same force. His foot hurts

The same amount because masses remain the same

Antilock brakes keep car wheels from locking and skidding during a sudden stop. Why does this help slow the car down?

Us>Uk so static friction is better. Static friction is greater than sliding friction

Alice and Bill are at the top of a cliff of height H. Both throw a ball with initial speed v0, Alice straight down and Bill straight up. The speeds of the balls when they hit the ground are vA and vB. If there is no air resistance, which is true?

Vb=va

If the velocity of a car is non zero can the acceleration of a car be zero.

Yes

You are trying to hit a friend with a water balloon. He is sitting in the window of his dorm room directly across the street. You aim straight at him and shoot. Just when you shoot, he falls out of the window! Does the water balloon hit him

Yes because gravity has the same effect on both

You are on the street, trying to hit a friend with a water balloon. He is sitting in his dorm room window above your position and is aiming at you with HIS water balloon! You aim straight at him and shoot and he does the same in the same instant. Do the water balloons hit each other?

Yes both have gravity

You are on the street, trying to hit a friend with a water balloon. He is sitting in his dorm room window above your position. You aim straight at him and shoot. Just when you shoot, he falls out of the window! Does the water balloon hit him?

Yes it hits because they both have the same y acceleration

You are a passenger in a car, not wearing a seat belt. The car makes a sharp left turn. From your perspective in the car, what do you feel is happening to you?

You are thrown right

When throwing a ball straight up, which of the following is true about its velocity and acceleration at the highest point

velocity=0 acceleration will not equal 0

You and your dog go for a walk to the park, on the way your dog takes many side trips to chase squirrels or examine fire hydrants. when you arrive at the park, do you and your dog have the same displacement

yes