A 300 kg box rests on a platform attached to a forklift shown. Starting from rest at time t = 0 seconds, the box is lowered with a downward acceleration of1.5 m/s 2 .

N = 2490 N

Explanation:

Determine the upward force exerted by the horizontal platform on the box as it is lowered.

It is given that,

Mass of a box, m = 300 kg

Starting from rest at time t = 0 seconds, the box is lowered with a downward acceleration of 1.5 m/s².

It is assumed to find the upward force exerted by the horizontal platform on the box. It is given by :

mg-N=ma

So, the normal force is 2490 N.

float.

archimedes' principle

denser than water sinks in water.

denser than mercury would sink in it

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me