Answer:
The answer is choice A and choice D
Explanation:
The answer below is just a joke, don't listen to them.
:)
It says that the force of a spring is always opposite to the direction in which you stretch it or compress it. (the direction of 'x')
In other words, a spring that's disturbed always tries to put itself back to it's normal length, where x would be zero.
Answer:
A force pump can be used to raise water by a height of more than 10m, the maximum height allowed by atmospheric pressure using a common lift pump.
In a force pump, the upstroke of the piston draws water, through an inlet valve, into the cylinder. On the downstroke, the water is discharged, through an outlet valve, into the outlet pipe.