Physics Midterm Review

A 10N force is applied to the right while two 5N forces are applied leftward. What is the sum of the forces acting on the object?

0 10N=10N

What is the acceleration of a 20kg mass if 30N of force is applied to it?

1.5m/s^2

What is the acceleration of a 5kg mass if 8N of force is applied to it?

1.6 m/s^2

What is the net force on a object if five 5N forces pull leftward while one 15N force pulls rightward?

10 left

What is the mass of an object if 10000N of force accelerates it at 10m/s2

1000kg

What is the force required to accelerate a 5kg mass at 2m/s2.

10N

What is the mass of an object if 10N of force accelerates it at 1m/s2

10kg

What is the force required to accelerate a 6kg mass at 3m/s2.

18N

What is net force on an object it two 15N forces pull leftward while one ten N force pulls rightward?

20 left

what is the acceleration of a 15kg mass if 50N of force is applied to it?

3.33m/s2

What is the mass of an object if 10N of force accelerates it at 2.5m/s2

4kg

What is the force required to accelerate a 4kg mass at 20 m/s2.

80N

An astronaut has a mass of 90 kg on the earth. The moon's gravity is 1/6 that of earth. On the moon the astronaut will have a mass of

90 kg

Which of the following statements are true of projectiles?

A projectile is a free-falling object A projectile experiences negligible or no air resistance A projectile must be accelerating in the downward direction A projectile does not have to have horizontal motion. A projectile could begin its projectile motion with a downward velocity

Which of the following statements are true of the horizontal motion of projectiles?

A projectile with a horizontal component of motion will have a constant horizontal velocity

Which of the following statements are true of the vertical motion of projectiles?

A projectile with an downward component of motion will have a downward component of acceleration The magnitude of the vertical velocity of a projectile changes by 9.8 m/s each second. The vertical velocity of a projectile is 0 m/s at the peak of its trajectory The vertical velocity of a projectile is unaffected by the horizontal velocity: these two components of motion are independent of each other. The peak height to which a projectile rises above the launch location is dependent upon the initial vertical velocity.

Mary and Debra stand on a snow-covered roof. They both throw snowballs with the same initial speed, but in different directions. Mary throws her snowball downward, at 30° below the horizontal; Debra throws her snowball upward, at 30° above the horizontal. Which of the following statements are true about just before the snowballs reach the ground below?

A) Debra's snowball will stay in the air longer than Mary's snowball D) Debra's snowball has exactly the same acceleration as Mary's acceleration

Newton's third law is known as

Action and reaction law

A pilot drops a package from a plane flying horizontally at a constant speed. neglecting air resistance, when the package hits the ground the horizontal location of the plane will

Be directly over the package

The moon is accelerated toward the Earth, so its gradually getting closer to the earth

False

Newton's second law is known as the Law of?

Force and Acceleration

_______and air resistance are examples of negative forces.

Friction

You are trying to cross a river that flows towards the south with a strong current. You start out in your motor-boat on the east bank desiring to reach the west bank directly west from your starting point. You should head your motorboat

In a general northwesterly direction

Newton's first law is known as the law of?

Interia

If a satellite moves with constant speed in a perfectly circular orbit around the earth, what is the direction of the acceleration of the satellite?

Inward toward the Earth

In question 51, the object will do which of the following?

It will move leftward with increasing speed.

A rock thrown from the upper edge of a tall cliff at some angle above the horizontal. It reaches its height point and starts falling down. Which of the following statements about the rock's motion are true just before it hits the ground?

Its horizontal velocity component is the same as it was just as it was launched.

James and John dive from an overhang into the lake below. James simply drops straight down from the edge. John takes a running start and jumps with an initial horizontal velocity of 25 m/s. Compare the time it takes each to reach the lake below if there is no air resistance.

James and John will reach the surface of the lake at the same time

For general projectile motion with no resistance, the horizontal component of a projectile's velocity?

Remains a non-zero constant

The acceleration of an object is directly related to the force exerted on the object. This is an example of Newtons

Second law

The acceleration of an object is equal to the force required to move the mass divided by its mass. This is an example of

Second law

A ball is thrown horizontally from the top of a tower at the same instant that a stone is dropped vertically. Which object is traveling faster when it hits the ground below if neither of them experiences any air resistance?

The ball

Which of the following statements are true about an object in two-dimensional projectile motion with no air resistance?

The horizontal acceleration is always zero and the vertical acceleration is always a non-zero constant downward

Which of the following statements are true of the horizontal motion of projectiles?

The horizontal velocity of a projectile is unaffected by the vertical velocity: these two components of motions are independent of each other. The horizontal displacement of a projectile is dependent upon the time of flight and the initial horizontal velocity The final velocity of a projectile is always equal to the initial horizontal velocity

James and John dive from an overhang into the lake below. James simply drops straight down from the edge. John takes a running start and jumps with an initial horizontal velocity of 25 m/s. If there is no air resistance when they reach the lake below.

The splashdown speed of John is larger than that of James

which of the following statements are true of the time of flight for a projectiles?

The time that a projectile is in the air is dependent upon the vertical component of the initial velocity For a projectile which lands at the same height that it is projected from, the time to rise to the peak is equal to the time of fall from its peak to the original height. For the same upward launch angles, projectiles will stay in the air longer if the initial velocity is increased.

An object moves in a circular path at a constant speed. Compare the direction of the object's velocity and acceleration vectors.

The vectors are perpendicular to each other

which of the following statements are true of the vertical motion of projectiles?

The vertical component of a projectile's velocity is changing The vertical component of a projectile's velocity is changing at a constant rate.

In air-free chamber, a pebble is thrown horizontally, and at the same instant a second pebble is dropped from the same height. Compare the times of fall of the two pebbles

They hit at the same time

The infinity gauntlet sitting on Mr. C's shelf exerts a downward force in response the surface pushes up with an equal force. This is an example of Newtons

Third law

Which of the following descriptions of moving objects accurately portray a projectile?

a free-falling object

Which of the following descriptions of moving object accurately portray a projectile?

an object upon which the only significant force is gravity a falling feather in a vacuum chamber a falling feather in a falling vacuum chamber

Mary and Debra stand on a snow-covered roof. They both throw snowballs with the same initial speed, but in different directions. Mary throws her snowball downward, at 30° below the horizontal; Debra throws her snowball upward, at 30° above the horizontal. Which of the following statements are true about just as the snowballs reach the ground below? (There could be more than one correct choice.) A) Debra's snowball will have a higher speed than Mary's snowball. B) Both snowballs will hit the ground with the same speed. C) Mary's snowball will have a higher speed than Debra's snowball. D) Mary's snowball reaches the ground before Debra's snowball. E) Both snowballs hit the ground at the same time.

b and d

A 10N net force right afts on an object at rest. which of the following describes the movement of that object?

it will move rightward with increasing velocity

During a crash you continue to move forward even as your car stops. This is an example of Newtons

first law

When you are drive fast through a curve and feel like want to continue moving straight, this is an example of Newtons

first law

When you pull on a table cloth suddenly, the dishes on the table remain in place. This is an example of newton's

first law

You stack a pile of poker chips on a playing card sitting on top of a cup. When you flick the cards, the chips fall into the cup. This is an example of Newton's

first law

_______is a push or pull

force

An object is in typical projectile motion moving upward toward the right. Disregarding air resistance which of the following is true?

gravity is the only force acting on the object

For general projectile motion with no air resistance, the horizontal component of a projectile's acceleration

is always zero

When the sum of all forces acting on an object is zero the object?

is in equilibrium nay be a rest may be moving or moving at constant velocity

The energy of motion is known as

kinetic energy

A car is moving rightward then slows to a stop. The acceleration of the vehicle is

leftward because the car is slowing down

Inertia is dependent on which of the following?

mass

The amount of matter that makes up an object is known as

mass

Friction and air resistance are known as _________forces because they always apply in the opposite direction of the object's motion.

negative

A player kicks a soccer ball in a high arc toward the opponent's goal. At the highest point in its trajectory

neither the ball's velocity nor its acceleration are zero

energy possessed due to position is known as

potential

For general projectile motion with no air resistance, the vertical component of a projectile's acceleration

remains a non-zero constant

If you drop a feather and hammer on the moon which will hit first?

same time

it takes 50N of force to accelerate a 10kg mass at 5m/s2 . This is an example of newton's

second law

it takes more force to accelerate a heavy mass than a light mass. This is an example of Newtons

second law

When a Delta 5 booster ignites, the gas produced from combustion of the fuel pushes against the rocket moving it forward while the exhaust escapes out the back of the rocket. This is an example of Newton's

third law

When you jump, you push on the earth and the earth pushes back against you. This is an example of newtons

third law

when you catch a ball, the ball pushes against you as you push against the ball. This is an example of newton's

third law

The _________of an object is dependent on both gravity and mass

weight

The ________of object is dependent on both gravity and mass?

weight