Final answer:
The boy loses approximately 2600 J of gravitational potential energy, which is option B. When he is 1m above the ground, his potential energy is 588 J. Upon landing, his potential energy is 0 J.
option b is the correct
Step-by-step explanation:
The question deals with gravitational potential energy (GPE), which is energy an object possesses because of its position in a gravitational field. GPE can be calculated using the formula GPE = mgh, where m is mass in kilograms, g is the acceleration due to gravity (9.8 m/s² on Earth), and h is the height in meters.
To calculate how much gravitational potential energy a 60 kg boy loses when he walks down a flight of stairs which is 4.5 m high, we use the formula:
GPE = mgh
= (60 kg) * (9.8 m/s²) * (4.5 m)
= 2646 J
However, since we are looking for an answer closest to the listed options, the correct answer can be approximated and rounded down to 2600 J, which is option B. The approximation is because of rounding the exact value to match the nearest option provided.
For part b, when the boy jumps and is 1m from the ground, his potential energy will be:
GPE = (60 kg) * (9.8 m/s²) * (1 m) = 588 J
When the boy lands on the ground, his potential energy will be 0 J because he is no longer elevated above ground level.
For reference, if a 70 kg person climbs 10 flights of stairs each 3 m high, the total potential energy gained would be:
GPE = (70 kg) * (9.8 m/s²) * (10 flights * 3 m) = 21000 J