Answer:
B. Gravitational force
Explanation:
The gravitational force of an object (also called weight) is given by

where m is the mass of the object and g is the acceleration of gravity, and it always points in the downward direction.
In this problem, the arrow labelled with 4 is the only force pointing downward: therefore, it must be the gravitational force.
The other arrows represent:
1 --> component of the gravitational force parallel to the plane
2 --> force of friction
3 --> component of the gravitational force perpendicular to the plane
the answer is 40.5 because you have to multiply the density and volume of the object to get the mass.
Answer:
20,000,000 N
Explanation:
First find the acceleration:
a = Δv / Δt
a = (0 − 40 m/s) / 0.010 s
a = -4000 m/s²
Next use Newton's second law to find the force on the car:
F = ma
F = (5000 kg) (-4000 m/s²)
F = -20,000,000 N
According to Newton's third law, the force on the wall is equal and opposite the force on the car.
F = 20,000,000 N