Answer:
Explanation:
Average speed = Total distance / Total time.
100 km/hr
r = 100 km / hr
t = 6 hours
d = 6 * 100 = 600 km
120 km / hr
r = 120 km / hr
t = 5 hour
d = 120 * 5
d = 600 km
Total distance = 600 + 600 = 1200 km
Total time = 5 hour + 6 hours = 11 hours.
Average speed = 1200 km / 11 hours = 109.1
W=mgh
W=(6)(9.8)(4)
W= 235.2J
Answer : The static friction depends on two factors
1. Roughness of the surface
2. Force
Explanation : Friction occur when surface is not smooth.
The formula of friction is

Static friction depends on the roughness of the surface and force which is trying to push to object along the surface.
Static friction is caused by the attraction between two surfaces that are in contact. when the surface will rough and the object will heavier then the force will be larger.
Answer:
decreases.
Explanation:
When the aircraft is flies from the warm air into the colder air then its speed will be decreases.
as we know that
we know mach number is constant
so that here Mach number M is expressed as
M =
.............................1
here u is Local flow velocity with respect to the boundarie and v is the speed of sound in the medium
If the aircraft flies from hot air to cold air, the speed of sound in the medium will decrease. But the Mach number remains constant. Therefore, the local flow velocity relative to the boundaries also decreases.