A cross-country skier moves 32 meters westward, then 54
1 answer:
Explanation:
It is given that, a cross-country skier moves 32 meters westward, then 54 meters eastward, and finally 68 meters westward.
The attached figure shows the whole scenario. He starts walking 32 m west and finally it walks 68 m west.
Let west is negative and east is positive.
Displacement = final position - initial position
= -68 - (-32)
= -36 m
The magnitude of displacement is equal to 30 m westwards.
You might be interested in
Consult the attached free body diagram.
By Newton's second law, the net force on the crate acting parallel to the surface is
∑ F[para] = (370 N) cos(-20°) - f = 0
(this is the x-component of the resultant force)
where
• (370 N) cos(-20°) = magnitude of the horizontal component of the pushing force
• f = magnitude of kinetic friction
The crate is moving at a constant speed and thus not accelerating, so the crate is in equilibrium.
Solve for f :
f = (370 N) cos(-20°) ≈ 347.686 N
The net force acting perpendicular to the surface is
∑ F[perp] = n - 1480 N - (370 N) sin(-20°) = 0
(this is the y-component of the resultant force)
where
• n = magnitude of normal force
• 1480 N = weight of the crate
• (370 N) sin(-20°) = magnitude of the vertical component of push
The crate doesn't move up or down, so it's also in equilibrium in this direction.
Solve for n :
n = 1480 N + (370 N) sin(-20°) ≈ 1606.55 N ≈ 1610 N
Then the coefficient of kinetic friction is µ such that
f = µn ⇒ µ = f/n ≈ 0.216
Answer:
C. 2.95 grams/cubic centimeter
Explanation:
Density can be defined as mass all over the volume of an object.
Simply stated, density is mass per unit volume of an object.
Mathematically, density is given by the equation;
The standard unit for the measurement of density of a substance is either kilograms per cubic meters or grams per cubic centimeters.
Hence, 2.95 grams/cubic centimeter is a correct measurement of density