The answer is d! I’m happy to help :)
Answer:
Part a)

Part b)

Explanation:
Part a)
If block is sliding up then net force must be zero and friction will be in opposite to the direction of motion of the block


so we have





Part b)
If block is sliding down then net force must be zero and friction will be in opposite to the direction of motion of the block


so we have





Answer:
The efficiency of Carnot's heat engine is 26.8 %.
Explanation:
Temperature of hot reservoir, TH = 100 degree C = 373 K
temperature of cold reservoir, Tc = 0 degree C = 273 K
The efficiency of Carnot's heat engine is
The efficiency of Carnot's heat engine is 26.8 %.
Answer:
The pickup truck and hatchback will meet again at 440.896 m
Explanation:
Let us assume that both vehicles are at origin at the start means initial position is zero i.e.
= 0. Both the vehicles will cross each other at same time so we will make equations for both and will solve for time.
Truck:
= 33.2 m/s, a = 0 (since the velocity is constant),
= 0
Using 
s = 33.2t .......... eq (1)
Hatchback:
,
= 0 m/s (since initial velocity is zero),
= 0
Using 
putting in the data we will get

now putting 's' value from eq (1)

which will give,
t = 13.28 s
so both vehicles will meet up gain after 13.28 sec.
putting t = 13.28 in eq (1) will give
s = 440.896 m
So, both vehicles will meet up again at 440.896 m.
Answer:
17.1
Explanation:
The distance ahead, of the deer when it is sighted by the park ranger, d = 20 m
The initial speed with which the ranger was driving, u = 11.4 m/s
The acceleration rate with which the ranger slows down, a = (-)3.80 m/s² (For a vehicle slowing down, the acceleration is negative)
The distance required for the ranger to come to rest, s = Required
The kinematic equation of motion that can be used to find the distance the ranger's vehicle travels before coming to rest (the distance 's'), is given as follows;
v² = u² + 2·a·s
∴ s = (v² - u²)/(2·a)
Where;
v = The final velocity = 0 m/s (the vehicle comes to rest (stops))
Plugging in the values for 'v', 'u', and 'a', gives;
s = (0² - 11.4²)/(2 × -3.8) = 17.1
The distance the required for the ranger's vehicle to com to rest, s = 17.1 (meters).