D is the answer. It is a firm statement.
Explanation:
Work done is given by the product of force and displacement.
Case 1,
1. A boy lifts a 2-newton box 0.8 meters.
W = 2 N × 0.8 m = 1.6 J
2. A boy lifts a 5-newton box 0.8 meters.
W = 5 N × 0.8 m = 4 J
3. A boy lifts a 8-newton box 0.2 meters.
W = 8 N × 0.2 m = 1.6 J
4. A boy lifts a 10-newton box 0.2 meters.
W = 10 N × 0.2 m = 2 J
Out of the four options, in option (2) ''A boy lifts a 5-newton box 0.8 meters'', the work done is 4 J. Hence, the greatest work done is 4 J.
Answer:
Answer C
Explanation:
The closer two masses are, the greater the gravity force between them.
This is shown in the formula
Fg = GMm/R²
Smaller distance R means greater force Fg
Explanation:
A.
Using the wave equation:
v = d/t
Where,
v = velocity
d = distance
= 23.5 km
= 23500 m
t = time
= 2m 30s = 150 s
v = 23500/150
= 156.7 m/s
B.
From the calculated value above, it can be seen that the velocity of the heat blast is >>> than the velocity of sound above sea level.
