The answer of this question is D. All of the above
Acceleration happen when an obeject change its velocity. It has nothing to do with speed.
The huge misconception about acceleration is when we thought it only aply if we increase our speed ( in a sport match, sportcaster often describe acceleration as an increase in players speed)
slower, faster, right , left, it does not matter, as long as that object change its velocity, it accelerates
Answer:
k = 5178.8 N/m
Explanation:
As we know that spring mass system will oscillate at angular frequency given as

now we have

now the maximum acceleration of the spring block system is at its maximum compression state which is given as

here A= maximum compression of the spring
so here in order to find maximum compression of the spring we will use energy conservation as we know that initial total kinetic energy of the car will convert into spring potential energy

here we know that
v = 85 km/h

now we have


now from above equation of acceleration we have



Answer:
114.44 J
Explanation:
From Hook's Law,
F = ke................. Equation 1
Where F = Force required to stretch the spring, k = spring constant, e = extension.
make k the subject of the equation
k = F/e.............. Equation 2
Given: F = 10 lb = (10×4.45) N = 44.5 N, e = 4 in = (4×0.254) = 1.016 m.
Substitute into equation 2
k = 44.5/1.016
k = 43.799 N/m
Work done in stretching the 9 in beyond its natural length
W = 1/2ke²................. Equation 3
Given: e = 9 in = (9×0.254) = 2.286 m, k = 43.799 N/m
Substitute into equation 3
W = 1/2×43.799×2.286²
W = 114.44 J
When hockey players push the puck along the ice it slides causing heat which melts the ice causing the friction against the ice to be less.
Answer:v=3.28 m/s
Explanation:
Given
mass of rock 
diameter of circle 
radius 
At highest Point

At highest Point N=0 because mass is just balanced by centripetal Force
thus 



