Answer:
D)378kJ
Explanation:
Applying,
E = F×d................ Equation 1
Where E = Energy expanded by the car, F = Wind resistance, d = distance
From the question,
F = 0.42v²............ Equation 2
Susbtitute equation 2 into equation 1
E = 0.42v²d.............. Equation 3
Given: v = 30 m/s, d = 1 km = 1000 m
Substitute these values into equation 3
E = 0.42(30²)(1000)
E = 378000
E = 378 kJ
Hence the right option is D)378kJ
The mass of the kid and the sled is 50.0 kg
Explanation:
The sled starts to move when the force applied becomes larger than the maximum force of static friction, which is given by

where
is the coefficient of static friction
m is the mass of the kid + the sled
is the acceleration of gravity
Here the sled starts moving when the force applied is 61.2 N, so

And we also know

Therefore, we can find the mass of the kid and the sled by re-arranging the equation:

Learn more about friction:
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Hey there!
The answer is C
Hope this helps you!
Always remember, you are A Work Of Art!
- Nicole <3 :)
Answer:
have a component along the direction of motion that remains perpendicular to the direction of motion
Explanation:
In this exercise you are asked to enter which sentence is correct, let's start by writing Newton's second law.
circular movement
F = m a
a = v² / r
F = m v²/R
where the force is perpendicular to the velocity, all the force is used to change the direction of the velocity
in linear motion
F = m a
where the force is parallel to the acceleration of the body, the total force is used to change the modulus of the velocity
the correct answer is: have a component along the direction of motion that remains perpendicular to the direction of motion