Answer:
320 N/m
Explanation:
F = k·Δx
where
F is the restoring force of the spring
k is the proportionality constant called the ‘spring constant’
Δx is the change in the spring’s position due to the deformation.
You need the k so
25 cm= 0.25m
k=F/∆x = 80/0.25 = 320 N/m
Answer:
Part a)

Part b)

Explanation:
As we know that by parallel axis theorem we will have

Part a)
here we know that for a stick the moment of inertia for an axis passing through its COM is given as

now if we need to find the inertia from its end then we will have



Part b)
here we know that for a cube the moment of inertia for an axis passing through its COM is given as

now if we need to find the inertia about an axis passing through its edge



A)
It is a launch oblique, therefore the initial velocity in the vertical direction is zero. Space Hourly Equation in vertical, we have:
Through Definition of Velocity, comes:

B)
Using the Velocity Hourly Equation in vertical direction, we have:
The angle of impact is given by:

If you notice any mistake in my english, please let me know, because i am not native.