Answer:
Heat transfer is an exchange of thermal energy between two objects. The rate of heat transfer depends upon the temperatures of each entity and the medium through which the thermal energy is being transferred. In cooking, heat transfer refers to heating your food items through a cooking appliance, such as a stove, fryer, microwave, or oven.
Explanation:
I hope it helps
Let us first calculate the average speed of David,
Av speed = Distance traveled/ Time taken
We have, distance = 70 miles
Time = 
hours = 1.75 hours
Av speed = 
= 40 miles/hour
Another 120 miles will be traveled in time, t = 120/40 = 3 hours
I believe it’s D, an applied force.
A reaction force seems to refer to Newton’s third law, but is relatively vague to be the answer to this question.
An expected force isn’t a concept nor the name of any subject of forces that is taught within the physics textbooks.
A positive force refers to direction, a negative force can have less, equal, or even more magnitude than the positive force, thus it contradicts itself. As that’s still a force that can push or pull.
So I believe it to be D.
Answer:
-360 kJ
Explanation:
Given:
m = 800 kg
v₀ = 30 m/s
v = 0 m/s
Δx = 75 m
Find: W
We can solve this using either forces or energy.
To use forces, first find the acceleration.
v² = v₀² + 2aΔx
(0 m/s)² = (30 m/s)² + 2a (75 m)
a = -6 m/s²
Then apply Newton's second law:
∑F = ma
F = (800 kg) (-6 m/s²)
F = -4800 N
Work is force times distance:
W = FΔx
W = (-4800 N) (75 m)
W = -360,000 J
W = -360 kJ
If you want to use energy instead:
work = change in energy
W = ΔKE
W = ½mv² − ½mv₀²
W = ½ (800 kg) (0 m/s)² − ½ (800 kg) (30 m/s)²
W = -360,000 J
W = -360 kJ
