Answer:
Usually the coefficient of friction remains unchanged
Explanation:
The coefficient of friction should in the majority of cases, remain constant no matter what your normal force is. When you apply a greater normal force, the frictional force increases, and your coefficient of friction stays the same. Here's another way to think about it: because the force of friction is equal to the normal force times the coefficient of friction, friction is increased when normal force is increased.
Plus, the coefficient of friction is a property of the materials being "rubbed", and this property usually does not depend on the normal force.
The total work is
(mass of the elevator, kg) x (9.8 m/s²) x (9.0 m) Joules .
Answer:
The units (km/h) tell you how to do this! 200km/3h = 66.66666666…. BUT technically you only have ONE significant digit: 3 so 66.666… rounded to ONE digit is 70km/h but that is probably not important in this intro class so V = 66.67 or 67 km/h
Answer:
0.488 m
Explanation:
If θ be the angle ladder makes with the plane
cos θ = 1.2 / 5
Tan θ = 4.04
Let the height a person of weight 600 N can climb be h from the ground .
Distance from the base point where ladder touches the floor = h / tanθ
= h / 4.04
Total reaction force = total downward force
R = 200 + 600
800 N
Frictional force = μ R
= .2 x 800
= 160 N
Taking moment of force about the point on the ladder where it touches the floor and balancing them
200 x 1.2 x .5 + 600 x h / tanθ = μ R x 1.2 / tanθ ( reaction at the top point of ladder where it touches the wall is R₁ and
R₁ =μ R )
= 200 x 1.2 x .5 + 600 x h / tanθ = 160 x 1.2 / tanθ
120 - 600 h / 4.04 = 47.52
120 - 47.52 = 600 h / 4.04
72.48= 148.51 h
h = 0.488 m
=
