A soccer ball is sitting in the middle of a soccer field during a game. When the referee blows his whistle, one of the players r
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Answer:
F = 9.81 [N]
Explanation:
To solve this problem we must use Newton's third le which tells us that the sum of forces on a body that remains static must be equal to one resulting from these forces in the opposite direction.
Let's perform a summation of forces on the vertical axis-y to determine the normal force N.
∑F = 0 (axis-y)
where:
m = mass = 4 [kg]
g = gravity acceleration = 9.81 [m/s²]
Now we know that the frictional force can be calculated using the following equation.
f = μ*N
where:
f = friction force [N]
μ = friction coefficient = 0.25
N = normal force = 39.24 [N]
Now replacing:
Then we perform a sum of forces on the X-axis equal to zero. This sum of forces allows us to determine the minimum force to be able to move the object in a horizontal direction.
∑F = 0 (axis-x)
If the coefficient was smaller, a smaller force (F) would be needed to start the movement, this can be easily seen by replacing the value of 0.25, by smaller values, such as 0.1 or 0.05.
If the coefficient were larger, a larger force would be needed.
Explanation:
Given that,
Mass of the car, m = 710 kg
Speed of the car, v = 23 m/s
Drag force, F = 500 N
(a) Let P is the power is required from the car's engine to drive the car on the level ground. Power is given by :
(b) Let P is the power is required from the car's engine to drive the car on up a hill with a slope of 2 degrees.
At this slope, force will be,
Total force will be :
Power is given by :
or
P = 17 kW