Answer:
4. 264.6J
5. 37.5J
6. 96J
7. 55Watts
8. 77.14m
9. 6s
10. 750Watts
Step-by-step explanation:
4). Mechanical energy (potential energy) = mass (m) × acceleration due to gravity (g) × height (h)
m = 3kg, h = 9m, g = 9.8m/s²
P.E = 3 × 9 × 9.8
= 264.6J
5). Kinetic energy (K.E) = 1/2 × m × v²
Where;
m = mass (kg) = 3kg
v = velocity (m/s) = 5m/s
K.E = 1/2 × 3 × 5²
K.E = 1/2 × 3 × 25
K.E = 1/2 × 75
K.E = 37.5J
6). Work done (J) = Force (N) × distance (m)
Force = 12N, distance = 8m
Work done = 12 × 8
= 96J
7). Power = work done (J) ÷ time (s)
Work done = 550J, time = 10s
Power = 550/10
= 55Watts.
8). Work done = force (F) × distance (m)
Work done = 540J, force = 7N, distance = ?
540 = 7 × d
540 = 7d
d = 540/7
d = 77.14m
9). Power = work done (J) ÷ time (s)
Work done = 300J, time = ?, Power = 50Watts.
50 = 300/t
50t = 300
t = 300/50
t = 6seconds.
10). Power = work done (J) ÷ time (s)
This means that;
Power = force × distance / time
Force = 300N, distance = 5m, time = 2s
Power = 300 × 5 ÷ 2
Power = 1500 ÷ 2
Power = 750Watts