Physics- FINAL

They will reach the ground at the same time

A 10 pound iron ball and a 2 pound iron ball are dropped simultaneously from a height of 100 meters. Neglecting air resistance, which ball will reach the ground first?

downward and equal to 9.8 m/s2

A body released from rest falls with an acceleration of 9.8 m/s2. If the same body is thrown upward at an angle, and air resistance is negligible, its acceleration after release will be

can change direction

A car traveling at constant speed

the car has an acceleration directed inward toward the center of the curve.

A car travels around a curve with constant speed. The correct statement from the following is

According to the first law of thermodynamics, a change in internal energy is caused either by doing work or moving heat. Without any ofther information, therefore, we don't know whether a heat interaction or a work interaction occured, but it has to be one of the two.

A container increases its temperature. Without any other information, is it possible to determine whether a work interaction or a heat interaction occurred? Please explain your answer.

bringing the arms and legs in a line with the body.

A dancer begins performing a pirouette with arms extended. (A pirouette is a complete spin about a vertical axis.) This motion is completed most easily when the rotational inertia is decreased by

billow outward from the load.

A dump truck has a loosely tied canvas over its empty bed, which is full of still air. As the truck speeds down the highway, the canvas will tend to

When the fluid moves into the smaller cross-sectional area pipe, it's velocity is going to increase. Therefore, according to Bernoulli's principle, the pressure is going to decrease.

A fluid flows through a pipe with a large cross-sectional area. Near the end of the pipe, the cross-sectional area decreases. What happens to the fluid's velocity and pressure when it moves into the smaller cross-sectional area pipe? Explain how you know.

the angular momentum of a spinning object can only be changed by applying a torque.

A football thrown with a spinning motion is more stable than one thrown without spin because

Acceleration

A quantity that is a measure of how the velocity of a body changes with time is

both strike at the same instant

A rifle bullet is fired horizontally at the same instant another bullet is allowed to drop from rest at the same height. Which bullet strikes the earth first?

4 m and 2 m

A string is held taut between two supports 2.0 m apart. The longest and next-longest possible wavelengths for standing waves are

the upward force by the cable is equal to the downward force of gravity

An elevator is being lifted upward at a constant speed by a steel cable. All frictional forces are neglected. In this situation, forces on the elevator are such that

greater than when the cube was floating at the top

An ice cube in a glass of water is pushed to the bottom of the glass and held there with a straw. Consequently, the buoyant force on the ice cube is now

When an object is accelerating along a curved path, the centripetal force comes into play. The centripetal force is pointed toward the center of the circular path and keeps the object moving around that path. What the rider feels is a fictitious force that you think you are feeling, but isn't actually there.

As a car goes around a curve, the static friction between the tires and the road keep the car following the circular path. Explain why a rider may feel pushed outward as they go around the curve.

still moving forward

At night, a submarine is moving through the darkness underwater when its highly sensitive hydrophones detect the sound of a stationary ship on the surface. Wary of the ship, the submarine comes to a full stop. In doing so, the frequency of the sound coming from the ship increases slightly. Therefore, the sub was ___________before it stopped.

The breaker is a necessary feature of a parallel circuit in order to prevent the circuit from being overloaded due to increased current as more and more devices are added.

Circuit breakers are wired into parallel circuits so that they will break when too many devices are added. Explain why this is a necessary feature of a parallel circuit as more and more devices are added to the circuit.

The internal energy of the steam will be higher

Compare the internal energy of one gram of steam to that of one gram of water if both are at 100°C.

is converted to work and to waste heat.

Energy added to a cyclical heat engine

Baking a cake in an oven is a combination of both conduction and radiation. Heat is distributed from the heating element by radiation. Along with this, heat absorbed by the pan is transferred to the cake via conduction.

Explain whether the baking of a cake in an oven is a conduction, convection, radiation, or work interaction. Explain how you know.

Doorknobs are typically placed far away from the hinges of the door in order to increase torque, therefore making it easier to open. Torque is increased by maximizing the distance between the applied force and the rotational point, which in this case is the hinges. Therefore, the further the doorknob is from the hinges, the stronger the torque, and the easier the door is to open.

Explain why doorknobs are typically placed far away from the hinges of a door in order to make it easier to open the door.

from hot to cold objects.

Heat is a form of energy, and it has long been known that heat energy will naturally flow

the force will be four times larger

How will the force between two charged objects change if the both charges are doubled in magnitude?

only electric charges in motion.

Magnetic fields affect

The overall purpose of the air bag is to increase impact time, therefore increasing the impulse produced, and thus protecting the person in the car by changing your momentum. So, if the air bag were to inflate too quickly, and the air bag was hard when the person impacted with it, the impact time is going to decrease and therefore decrease the impulse produced.

Normally air bags keep us safe in a car. At one time, some air bags had a habit of inflating too quickly, so that they were very hard when someone ran into the air bag. Using Impulse and Momentum concepts, explain why this could be bad for someone

According to Newton's 3rd law, an action reaction pair must be exerted on different bodies, therefore the weight and normal force from the chair is not an action reaction pair since they are acting on the same body.

The weight of a chair is exactly equal to the normal force acting on the chair, but it points in the opposite direction. Explain why these two forces (weight of chair and normal force on chair) are NOT Newton's 3rd Law pairs.

Horizontal velocity won't affect the vertical position, so they will all reach the bottom of the falls at the same time.

There is a long history of people climbing into barrles of various forms and riding them over Niagara Falls. Three friends decide to try this out in separate barrels. Consider the friends and their velocities below: 1. Bill and his barrel have a mass of 76 kg and they launch horizontally off of the falls at a speed of 15 m/s. 2. Ted and his barrel have a mass of 125 kg and they launch horizontally off of the falls at a speed of 15 m/s. 3. Rufus and his barrel have a mass of 76 kg and they launch horizontally off of the falls at a speed of 25 m/s. Which of the three friends reaches the bottom of the falls first (assuming they leave the falls at the same instant)?

A transformer will not work if the input is a DC voltage source because the current only flows in one direction. For a transformer to work, there must be an alternating current to create a changing magnetic field. According to Faradays's Law, this changing magnetic field will in turn create a change in voltage, which is how a transformer works.

Transformers rely on Faraday's Law. Considering Faradays's Law, explain why a simple transformer needs to have an ac signal through the primary coil instead of a dc signal.

the electric field at the position of the smaller charge increases.

Two equal positive charges are near each other. If we increase the amount of charge on just one of them, then

Interference

Under the correct conditions, two light waves can produce regions of reinforcement and regions of cancellation. This phenomenon is known as

If the second hill of a roller coaster is taller than the first hill, the roller coaster will not be able to get over the second hill because all of the car's kinetic energy after the first hill will have been converted back to potential energy-- meaning that the car could only reach a height equal to the height of the first hill.

Use Energy concepts to explain whether a roller coaster car can get over the second hill of the track if the second hill is taller than the first hill.

apply more torque to the nut

Using a longer-handled wrench to loosen a tight nut allows you to

Mechanical advantage is the ratio of the output force to the input force. The difference between the two is whether or not we assume friction to be involved. Ideal Mechanical Advantage assumes no friction (distance of effort/distance of resistance), while Actual Mechanical Advantage assumes there is friction (force of resistance/force of effort).

What is Mechanical Advantage? Describe the difference between Ideal Mechanical Advantage and Actual Mechanical Advantage.

"follow through" on the swing, which increases contact time.

When a baseball bat hits the ball, the impulse delivered to the ball is increased by

Sound, water, and light

Which of the following waves exhibit interference?

Testability

Which of these criteria best distinguish between explanations provided by science and those provided by religion?

According to Newton's 1st law, when you brake, the notebook sitting on the passenger seat is going to continue to accelerate at the same speed the car was traveling before you hit the brakes. Objects in motion stay in motion, objects at rest stay at rest, UNLESS acted upon by an outside force.

You are driving down the road at 60 MPH when you see a car stopped in the lane in front of you. You slam on the brakes to avoid a collision. Using Newton's Laws, explain what happens to the notebook that is sitting on the passenger seat as you brake.

energy transferred to a body because of a difference in temperature.

The term heat in physics is

agree to have her wear the same color socks for a month

Suppose that a friend states the hypothesis that the color of socks that she wears on a given day, brown or black, will determine whether the stock market will go up or down. She can cite several instances in which this hypothesis has been apparently verified. Which of the following actions would help to verify her hypothesis? Check all that apply.

turning the headlights on, replacing the battery with another new battery

Suppose that your car will not start and you form the hypothesis that the battery is dead. Which of the following would be a test of that hypotheses? Check all that apply.

the amount of charge (measured in Coulombs) that passes a point (in the circuit) in 1 second.

The current (measured in amperes) in a circuit is

measurements are needed to prove ideas true or false

The development of physics concepts depends heavily on measurements because

a S pole, because it attracts the N pole of your compass needle.

The magnetic pole near the Earth's north geographic pole actually has to be

Frequency

The pitch of a sound is determined primarily by its