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Answer:
B
Explanation:
The question does not specify any outside forces that could slow down the ball horizontally. There fore the ball does not accelerate or decelerate horizontally. Therefore, a = 0m/s2
Work = (force) x (distance)
Force = weight of the barbell = (mass) x (gravity) = (2.5 kg) x (9.8 m/s²)
Work = (2.5 x 9.8 newtons) x (3 meters) = 74 newton-meters = 74 joules.
It takes 74 joules to lift the 2.5-kg load 3 meters up off the floor.
After that, as long as the load is held motionless, no more work is done.
Answer:
A. he can hear music coming from the radio.
Explanation:
Jeff knows that the radio produces sound energy because he can hear music coming from the radio.
The music from the radio is a form of sound energy.
- Sound energy is a form of energy dissipated from a body and can be discerned by humans.
- Sound is a mechanical wave that requires a material medium for its propagation.
- It travels by series of rarefaction and compression along its path of motion.
- Since sound energy is an energy in motion, it is a kinetic energy.
- It travels parallel to its source and therefore, it is a longitudinal wave.