Answer:
500 N
Explanation:
Since the work done on the spring W = Fx where F = force applied and x = compression length = 0.170 m (since the spring will be compressed its full length when the force is applied)
Since W = 85.0 J and we need to find F,
F = W/x
= 85.0 J/0.170 m
= 500 N
So, the magnitude of force must you apply to hold the platform stationary at the final distance given above is 500 N.
Answer:
Part a)

Part b)

Explanation:
Since the ball and rod is an isolated system and there is no external force on it so by momentum conservation we will have

here we also use angular momentum conservation
so we have

also we know that the collision is elastic collision so we have

so we have

also we know

also we know

so we have


now we have


Part b)
Now we know that speed of the ball after collision is given as

so it is given as

Hello!
Answer:
When a gas gets hot it should go up because of the pressure.
Explanation:
Hope this helps!
Answer:
1) current = I
2) Resistance = V/I
3) current = 2I
4) resistance = V/2I
5) current = 3I
6) Resistance = V/3I
7) Current = 4I
8) Resistance = V/4I
Explanation:
When one bulb is connected across the battery then let say the current is given as I
Then resistance is given as

When two bulbs are in parallel with the battery then
total current becomes twice of initial current
so we have
current = 2I
Resistance of the circuit is now

When three bulbs are in parallel with the battery then
total current becomes three times of initial current
so we have
current = 3I
Resistance of the circuit is now

When four bulbs are in parallel with the battery then
total current becomes four times of initial current
so we have
current = 4I
Resistance of the circuit is now

Weight equals mass times gravitational acceleration=400N, so mass=400/9.8=41kg approx.