Questions 1-3 Refer to the following situation A block m with mass 7kg moves up

Question

Questions 1-3 Refer to the following situation A block m with mass 7kg moves up an inclined plane with an initial velocity vo-4.7m/s. The inclined plane is at an angle of 450 from the horizontal. The coefficient of kinetic friction between the block and the incline is 0.25. D-lm Vo-4.7m/s Hk-0.25 0-45° Questions 4-8 Refer to the following situation A block of mass M-2 kg is held at rest compressed a distance d - 0.2 m. The block is then released, and it travels up a frictionless ramp t at the end of a spring of spring constant k 3500 N/m. The spring is

Explanation / Answer

a) Traveling up the incline, the work done on the block by friction is

W = -kmgDcos

where k = Coefficient of friction, D = Distance travelled, = Angle of inclined plane

b) As the block moves up the inclined plane, there are two forces that cause it to decelerate. These forces are the component of its weight that is parallel to the inclined plane and the friction force.

Force parallel = mg*sin
Ff = k*mg*cos
Total force = mg*sin + k*mg*cos

To determine the rate at which the velocity is decreasing, divide this force by the block’s mass.

a = g*sin + k*g*cos  

To determine the block’s velocity after moving 1 meter up the incline, use the following equation.

vf^2 = vi^2 + 2 * a * d
vf^2 = vi^2 + 2*-(g*sin + k*g*cos)*1
vf^2 = vi^2 + 2*- g*sin - k*g*cos
vf = (vi^2 + 2*- g*sin - k*g*cos) = (4.7^2 + 2*- 9.8*sin45 - 0.25*9.8*cos45) = 2.183 m/s

c) As velocity is independent of mass so it will remain same.

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