A 4 kg block is launched up a frictionless inclined plane by a spring as shown i
ID: 1437606 • Letter: A
Question
A 4 kg block is launched up a frictionless inclined plane by a spring as shown in the figure below. The plane is inclined at 30 and the spring constant is 800 N/m . The block is initially pushed against the spring in order to compress the spring 0.10 m , and then it is released.
A. Calculate the magnitude of the acceleration of the block the moment after it is released.
B. What is the direction of the acceleratiion of the block the moment after it is released?
C. Calculate the acceleration when the spring reaches the point where its compression is 0.07 m .
D. What is the magnitude of the acceleration when the spring reaches the point where its compression is zero?
E. What is the direction of the acceleration when the spring reaches the point where its compression is zero?
Explanation / Answer
a) along the incline,
Fnet = spring force - gravitational force = ma
800(0.10) - (4 x 9.8 x sin30) = 4a
a = 15.1 m/s^2
b) upwrd along the incline,
c) 800(0.07) - (4 x 9.8 x sin30) = 4a
a = 9.1 m/s^2
d) 800(0) - (4 x 9.8 x sin30) = 4a
a = - 4.9 m/s^2
4.9 m/s^2 donwards
E) downwards along the incline.