Answer:
v = 21.25 km/h
The average velocity is 21.25km/h
Explanation:
Average velocity = total displacement/time taken
v = d/t
Given;
A car travels 50 km in 25 km /h
d1 = 50km
v1 = 25km/h
time taken = distance/velocity
t1 = d1/v1
t1 = 50/25 = 2 hours
and then travels 60km with a velocity 20 km/h
d2 = 60km
v2 = 20km/h
t2 = d2/v2 = 60/20
t2 = 3 hours
and then travels 60km with a velocity 20 km/h in the same direction
d3 = 60km
v3 = 20km/h
t3 = d3/v3 = 60/20
t3 = 3 hours
Average velocity = total displacement/total time taken
v = (d1+d2+d3)/(t1+t2+t3)
v = (50+60+60)/(2+3+3)
v = 170/8
v = 21.25 km/h
The average velocity is 21.25km/h
Answer:
Frictional force, F = 45.9 N
Explanation:
It is given that,
Weight of the box, W = 150 N
Acceleration, 
The coefficient of static friction between the box and the wagon's surface is 0.6 and the coefficient of kinetic friction is 0.4.
It is mentioned that the box does not move relative to the wagon. The force of friction is equal to the applied force. Let a is the acceleration. So,



Frictional force is given by :


F = 45.9 N
So, the friction force on this box is closest to 45.9 N. Hence, this is the required solution.
Answer:C
Explanation:
Partially submerged block along with vessel is accelerated upwards .
Initially the block weight is supported by buoyant force such that it is in equilibrium.
when the system start accelerating upwards then the effective gravity will be
g+a where a is the acceleration of the system.
so only net gravity is increased so block will not ascend or descend.
Mathematically


where
density of liquid
V=volume of object inside the water
Answer:
The Answer Is A,C,D
Explanation:
The gravitational pull from the moon make bigger waves'
There would be no moon for eclipses
There would be more sun and no moon