true or false
1. The work required to stretch a spring changes linearly with the amount of strech?
2. The kinetic energy of an object increases linearly as the velocity of the object increases?
3. Kinetic energy is proportional to speed?
4. Kinetic energy is proportional to mass?
5. Kinetic energy is a scaler quantity?
6. Power is a vector quantity?
7. Work done by the force of friction can be positive or negative?
8. Work done by a force on an object can be positive or negative quantity?
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1. False. The work required to stretch a spring follows Hooke's Law and is directly proportional to the displacement or stretch of the spring, not linearly. The equation to calculate the work done on a spring is W = (1/2)kx^2, where W is the work, k is the spring constant, and x is the displacement from the equilibrium position.
2. False. The kinetic energy of an object increases with the square of its velocity, not linearly. The equation to calculate kinetic energy is KE = (1/2)mv^2, where KE is the kinetic energy, m is the mass of the object, and v is its velocity.
3. True. Kinetic energy is indeed proportional to speed. As stated in the equation above, KE = (1/2)mv^2, the kinetic energy increases with the square of the velocity.
4. True. Kinetic energy is directly proportional to the mass of an object. Again, in the equation KE = (1/2)mv^2, the kinetic energy increases with the mass.
5. True. Kinetic energy is a scalar quantity, meaning it only has magnitude and does not have a direction associated with it. It is different from vector quantities like velocity or force, which have both magnitude and direction.
6. False. Power is not a vector quantity; it is a scalar quantity. Power represents the rate at which work is done or energy is transferred. It is given by the equation P = W/t, where P is power, W is work, and t is time. Power only has magnitude and no directional component.
7. True. The work done by the force of friction can be either positive or negative, depending on the circumstances. If the force of friction opposes the motion of an object, the work done is considered negative. Conversely, if the force of friction assists the motion of an object, the work done is considered positive.
8. True. Similar to the work done by the force of friction, the work done by any force on an object can also be positive or negative. It depends on the angle between the force vector and the displacement vector. If the force and displacement are in the same direction, the work done is positive. If they are in opposite directions, the work done is negative.