11. a student lifts a 25 kg mass a vertical distance of 1.6 m in a time of 2.0 seconds. a. find the force needed to lift the mass (in n).

245 Newtons

Explanation:

The force needed is simply the same as that of gravity for an object with mass 25. That is: mass times g, which in this case gives 25 kg times 9,8 m/squared seconds. And that equals 245 Newtons.

A student lifting a mass of 25Kg in vertical distance of 1.6 m in a time of 2.0 seconds requires a force of 245.25 N to lift the mass.

Explanation:

Given:

Mass m=25 kg

distance d =1.6 m  

time= 2.0 seconds  

To find  :

Force required to lift the mass=?

We know

where  

g is a gravitational foce and is a constant

Also  

substituting the given values,

Result:

Thus ,a student lifting a mass of 25Kg in vertical distance of 1.6 m in a time of 2.0 seconds requires a force of 245.25 N to lift the mass.

double the distance = divide strength by 4

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form