CORRECT ANSWERS ARE BOLDED BELOW, SHOW WORK ON HOW TO GET THOSE ANSWERS PLZ! The
ID: 1438960 • Letter: C
Question
CORRECT ANSWERS ARE BOLDED BELOW, SHOW WORK ON HOW TO GET THOSE ANSWERS PLZ!
The correct answes are 20) C and 21) B
Name Student ID Score Last First Use the following scenario for the next two problems. B/m A block of mass m is on a rough incline and held against a compressed spring at Position A as shown. The angle of the incline from horizontal is A/m The coefficient of kinetic friction between the block and the incline surface is ur. The block is then let go, and reaches the maximum height of H at position B when the block mo nentarily sto 20. What is the acceleration of the block after it leaves the spring? A) B) C) D) g(A+sin gu sin-cos6 E 8(A coso-sine) 21. If the initial compression of the spring is x, and the spring constant is k, how much mechanical energy of the block-spring-earth system is dissipated as the block moves from Position A to Position B? D) mgH E) umgiExplanation / Answer
20) Gravitational force is resolved into two components
wx = mgcos(theta) , wy = mg sin(theta)
net force along perpendicular to the incline is zero
Fy =0
N = mgcos(theta) ...(1)
Friciton force Fk = uk N = uk *mgcos(theta)
Net force along parallel to incline surface Fx =ma
Fk + mgsin(theta) =ma
uk*mgcos(theta) +mg*sin(theta) = ma
a = g[uk*cos(theta) + sin(theta)]
correct option is (C)
21) From conservation of energy
(K1+U1)at bottom = (K2+U2)at top
K1 + (1/2)kx^2 = K2 + mgH
K2 -K1 = (1/2)kx^2 - mgH
from work energy thorem W = chane in kinetic energy
W = (1/2)kx^2 - mgH
correct option is (B)