Physics Final Exam Multiple Choice

In 2-d projectile motion with no air resistance, the object only experiences acceleration due to gravity. The acceleration of the object is +g when the object is rising and -g when it is falling, as gravity acts in the opposite direction of motion. At the highest point of its trajectory, the object momentarily stops moving vertically, so the vertical acceleration is zero at that point. However, the horizontal acceleration is always zero as there is no force acting horizontally. The velocity of the object changes direction but its speed remains constant throughout the motion.

During a head-on collision between a small car and a large truck, the momentum of the car and the momentum of the truck are each conserved. However, the momentum of the car-truck system is also conserved. This means that the total momentum of the system before the collision is equal to the total momentum after the collision. While the individual momenta of the car and the truck may change, their combined momentum remains constant.

On a cold day, a piece of metal feels much colder to the touch than a piece of wood because of the difference in their thermal conductivity. Thermal conductivity refers to the ability of a material to conduct heat. Metal has a higher thermal conductivity compared to wood, meaning it can transfer heat more efficiently. Therefore, when we touch a piece of metal, it quickly absorbs the heat from our skin, making it feel colder. On the other hand, wood has lower thermal conductivity, so it does not absorb heat as quickly, resulting in a less cold sensation when touched.

When a rigid object rotates about a fixed axis, all the points in the object have the same angular speed. This means that each point in the object travels through the same angle in the same amount of time. The angular speed is a measure of how quickly the object rotates, and it is constant for all points in the object because they are all rotating about the same axis. This is true regardless of the distance from the axis or the size of the object.

The specific heat capacity is a measure of the amount of heat energy required to raise the temperature of a substance. In this case, the specific heat capacity of aluminum is more than double that of copper, which means that aluminum can absorb more heat energy per unit mass compared to copper. However, the question states that both the aluminum and copper are in thermal contact, which means that they will exchange heat until they reach thermal equilibrium. During this process, the aluminum will transfer heat to the copper, causing its temperature to rise, while the copper will transfer heat to the aluminum, causing its temperature to decrease. As a result, both objects will experience the same magnitude of gain or loss of heat.

The gas does work during one cycle when it undergoes a change in volume and pressure. In this case, the gas goes from p0v0 to 3 p0v0 on the pV diagram. The work done by the gas can be calculated by finding the area under the curve on the pV diagram. Since the gas expands and does work, the area under the curve is positive. Therefore, the work done by the gas during one cycle is 3 p0v0.

The pressure is the same at each of the labeled points because the fluid is in equilibrium. In a fluid at rest, the pressure is determined by the depth of the fluid and the density of the fluid. Since the fluid in each section is at the same height and density, the pressure at each point will be the same.

When the bimetallic strip is uniformly heated, the metal with the higher coefficient of thermal expansion (metal G) will expand more than the metal with the lower coefficient of thermal expansion (metal H). This causes the strip to curve downward because metal G is expanding more and pushing against metal H, causing the strip to bend in that direction.

Since the car is slowing down, its acceleration must be negative. As the car is traveling to the west and slowing down, the acceleration is in the opposite direction to its motion. Therefore, the acceleration is toward the east.

The magnitude of acceleration is the greatest when the kinetic energy is a minimum. This is because in simple harmonic motion, the acceleration is directly proportional to the displacement from the equilibrium position. When the kinetic energy is at a minimum, the velocity and displacement are also at a minimum, which means the object is closest to the equilibrium position. At this point, the acceleration is the greatest as the object is rapidly changing direction and accelerating towards the equilibrium position.

When the temperature of the flat steel plate is increased, the plate expands due to thermal expansion. Since the hole is a part of the plate, it will also expand along with the plate. This is because the material of the plate and the hole have similar properties and will expand or contract in the same way when subjected to temperature changes. Therefore, the hole will always expand with the plate.

In simple harmonic motion, the speed is greatest when the magnitude of the acceleration is a minimum. This is because the acceleration is directly proportional to the displacement and opposite in direction. When the displacement is at its maximum, the acceleration is at its minimum, resulting in the highest speed. Conversely, when the displacement is at its minimum, the acceleration is at its maximum, resulting in the lowest speed. Therefore, the speed is greatest when the magnitude of the acceleration is a minimum.

The friction force on the car due to the road is directed perpendicular to the curve inward. This is because the car is moving in a circular path, and in order to maintain this curved motion, there must be a force acting towards the center of the circle. This inward-directed friction force provides the necessary centripetal force to keep the car moving in the circular curve.

In general projectile motion with no air resistance, the vertical component of a projectile's acceleration remains a non-zero constant. This means that throughout the entire motion, the acceleration in the vertical direction remains the same and does not change. The force of gravity acts vertically downward, causing the object to accelerate downward at a constant rate. This constant acceleration is what allows the projectile to follow a curved path in the vertical direction.

Salt water is denser than fresh water because it contains more dissolved salts and minerals. When a ship floats in water, it displaces a volume of water equal to its own weight. Since salt water is denser, it requires less volume to support the same weight compared to fresh water. Therefore, the volume of water displaced in salt water is less than in fresh water.

The work done by gravity is negative on the way up because the force of gravity acts in the opposite direction of the displacement. When the ball goes down, the work done by gravity is positive because the force of gravity is in the same direction as the displacement.

An object having constant non-zero velocity means that its speed and direction of motion are constant. On the other hand, changing acceleration implies that the rate of change of velocity is not constant. This situation is impossible because if the velocity is constant, there should be no change in acceleration. Acceleration is the rate at which velocity changes, so if the velocity is constant, there should be no changing acceleration.

The process shown on the pV diagram is an isobaric expansion because the pressure remains constant throughout the process. In an isobaric expansion, the volume of the system increases while the pressure remains the same. This can be seen in the diagram where the line representing the process is horizontal, indicating that the pressure is constant.