Answer:
Mike can travel 80 Km in 4 hours
Answer:
b. 0.034
Explanation:
The heat transfer coefficient of a material (U-value) is equal to the reciprocal of its R-value, therefore:

where
R is the R-value of the material
For the insulator in this problem,
R = 29
Substituting into the equation, we find the heat transfer coefficient:

The frictional force is directly proportional to the force that is perpendicular on the surface.
When the body is placed on a horizontal level with zero inclination, the only force acting on the body is the gravitational force which always pulls the body down. The gravitational force, in this case, is the perpendicular force to the surface. Accordingly, this entire force is used to generate friction
Now as the inclination of the surface increases, the gravitational force is no longer the perpendicular force of the body, its value decreases, which means only a part is used to generate frictional force. Consequently, frictional force decreases.
When the inclination reaches 90 degrees, the gravitational force does not act along the normal and accordingly, no friction force is generated.
Answer:
Time, t = 0.87 seconds
Explanation:
Given that,
Initial velocity of the object, u = 4.3 m/s
The coefficient of kinetic friction between horizontal tabletop and the object is 0.5
We need to find the time taken by the object for the object to come to rest i.e. final velocity will be 0.
Using first equation of motion to find it as :

a is the acceleration, here, 


So, the time taken by the object to come at rest is 0.87 seconds. Hence, this is the required solution.
Answer:
22.02 m
Explanation:
given,
Force, F = 107 N
angle made with horizontal = 13.5◦
Power develop by the lawn roller = 69.4 W
time = 33 s
distance = ?
Force along horizontal= F cos θ
= 107 cos 13.5°= 104 N
Power = 
69.4 = 
W = 2290.2 J
Work done= Force x displacement
displacement= 
= 22.02 m