If a 28-N force causes a rock to accelerate at 4 m/s/s, what is the mass of the rock?

7kg

Explanation:

Given parameters:

Force on the rock  = 28N

Acceleration  = 4m/s²

Unknown:

Mass of the rock  = ?

Solution:

According to newton's second law of motion;

           Force  = mass x acceleration

Insert the given parameters to find the mass;

         28  = mass x 4

             mass  =   = 7kg

falling water hydro = water .. spectcular places these plants are

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.