I would assume air resistance is negligible and so the acceleration of the package would be approximately 9.81 m/s².
Taking downwards as positive, use v²=u²+2as.
v²=(-2)²+2(9.81)(14)
v=16.7 m/s
Explanation:
Displacement = 5 km
A.
Converting km/h to m/s,
10 km/h * 1000 m/1 km * 1 h/3600 s
= 25/9 m/s
Remember,
700 watt = 700 J/s
Velocity = displacement/time
Time = 5000/(25/9)
= 1800 s
Energy = power * time
= 700 * 1800
= 1,260,000
= 1260 kJ
B.
Converting km/h to m/s,
3 km/h * 1000 m/1 km * 1 h/3600 s
= 5/6 m/s
290 watt = 290 J/s
Velocity = displacement/time
Time = 5000/(5/6)
= 6000 s
Energy = power * time
= 290 * 6000
= 1,740,000
= 1740 kJ
C.
Walking burns more energy; 1,740,000 joules. It burns more because you walk for a greater period of time.
<u>Latent hea</u>t is related to changes in phase between liquids ,gases and solids.
<u>Sensible heat</u> is related to changes in temperature of a gas or object with no change in phase.
Answer:
Due to the resistance of air, a drag force acts on a falling body (parachute) to slow down its motion. Without air resistance, or drag, objects would continue to increase speed until they hit the ground. The larger the object, the greater its air resistance. Parachutes use a large canopy to increase air resistance. Also, Once the parachute is opened, the air resistance overwhelms the downward force of gravity. The net force and the acceleration on the falling skydiver is upward. An upward net force on a downward falling object would cause that object to slow down. The skydiver thus slows down. Sorry if not helpful.
