Hello. This question is incomplete. The full question is:
Two blocks are stacked on top of each other on the floor of an elevator. For each of the following situations, select the correct relationship between the magnitudes of the two forces given.
The elevator is moving downward at a constant speed.
The magnitude of the force of the bottom block on the top block is _____ the magnitude of the force of the earth on the top block.
Answer:
The magnitude of the force of the bottom block on top block is equal to the magnitude of the force of the top block on bottom block.
Explanation:
As the elevator is descending, there is only a normal force being applied to the lower surface of the block. This force has a magnitude equal to the force of the upper block, because the only acceleration that is acting in this case is the force of gravity. From that force, the resulting force is zero.
Answer:
The car will make the turn perfectly
Explanation:
Given that the centripetal force= mv^2/r
M= mass of the car
v = speed of the car
r= radius
Hence;
F = 1000 × (14)^2/50
F= 3920 N
The frictional force = μmg
μ = coefficient of static friction
m= mass
g = acceleration due to gravity
Frictional force= 0.6 × 1000× 10
Frictional force = 6000 N
The car will not skid off the curve because the frictional force is greater than the centripetal force.
Answer:
e. TA>T>Tc
Explanation:
a) In this case, we cannot say for sure QA>QB>QC. This is because the magnitude of the heat flow will depend on the specific heat and the mass of each sample. Due to the equation:

if we did an energy balance of the system, we would get that>
QA+QB+QC=0
For this equation to be true, at least one of the heats must be negative. And one of the heats must be positive.
We don't know either of them, so we cannot determine if this statement is true.
b) We can say for sure that QA<0, because when the two samples get to equilibrum, the temperatrue of A must be smaller than its original temperature. Therefore, it must have lost heat. But we cannot say for sure if QB<0 because sample B could have gained or lost heat during the process, this will depend on the equilibrium temperature, which we don't know. So we cannot say for sure this option is correct.
c) In this case we don't know for sure if the equilibrium temperature will be greater or smaller than TB. This will depend on the mass and specific heat of the samples, just line in part a.
d) is not complete
e) We know for sure that A must have lost heat, so its equilibrium temperature must be smaller than it's original temperature. We know that C must have gained heat, therefore it's equilibrium temperature must be greater than it's original temperature, so TA>T>Tc must be true.
As per kinematics equation we know that
final speed of the car = 0 m/s
initial speed is given as 30 m/s
distance moved = 100 m
now we have



now braking force is given as

now for mass we know that the weight of car is

so mass of car is

now we have

Part b)
Again we have
final speed of the car = 0 m/s
initial speed is given as 30 m/s
distance moved = 10 m
now we have



now braking force is given as

mass of car is

now we have

Answer:
i think the answer is 50 kW.h