Answer:
17. h = l − l cos θ
18. 1.40 m
Explanation:
Let's call d the height of the triangle. We can then say:
h = l − d
Using trig, we can write d in terms of l and θ:
d = l cos θ
h = l − l cos θ
If l = 6 m and l cos θ = 40°:
h = 6 − 6 cos 40
h ≈ 1.40
Plug given values in SI units to get electric field.
Answer:
178.75 N
Explanation:
The force necessary to start moving the crate must be equal to or more than the frictional force (resistive force) acting on the crate but moving in an opposite direction to the frictional force.
So, we find the frictional force, Fr:
Fr = -μmg
Where μ = coefficient of friction
m = mass
g = acceleration due to gravity
The frictional force is negative because it acts against the direction of motion of the crate.
Fr = -0.57 * 32 * 9.8
Fr = - 178.75 N
Hence, the force necessary to move the crate must be at least equal to but opposite in direction to this frictional force.
Therefore, this force is 178.75 N
