A ball of mass 4kg is lightly dropped into a tub with a base of 1m^2. After it sinks to the bottom, the water rises by 2.5mm. Determine the density of the ball. a) 40 kg/L
b) 4.4 kg/L
c) 1.6 kg/L​

Let h be the height of the water in the tube. Then the total volume of water is

(h m) (1 m²) = h m³

After dropping the ball into the water, the height of the water changes to

h m + 2.25 mm = (h + 0.0025) m

and so the contents of the tub take up (h + 0.0025) m³ of volume.

This means the ball displaces

(h + 0.0025) m³ - h m³ = 0.0025 m³

of water, which is to say that this is volume of the ball.

With a mass of 4 kg, you would find its density to be

(4 kg) / (0.0025 m³) = (4 kg) / (2.5 L) = 1.6 kg/L

given data:

determine the horse power (h.p) = ?

force applied to move the box(f) = 10 pounds,

box lifted from a distance         (d) = 3 feet

time taken to lift                         (t) = 10 sec,

the horse power is defined as amount of work required to move a load. the horse power is equal to 550 foot-pound per second

                  1 h.p   = 550 foot-pound/second

it can also be defined as the the load that need to be move a body for certain distance in a certain amount of time.

mathematically,

                      h.p = (force × distance)/ time

                            = (10 × 3)/ 10

                            = 30/10

                            = 3 foot -pound/sec

hence, the horse power is needed to move the box is 3 foot-pound/second

important note: 1 h.p = 550 foot-pound/second = 746 watts