Answer:
0.75 g/cm^3
Explanation:
The formula for density:

Where m is the mass and V is the volume.
So, we can substitute values for m and V:

Therefore, the density is 0.75 g/cm^3 (watch the units!)
Time=speed/acceleration
Gravitaional Acceleration=9.8 m/s^2
Speed=24.5 m/s
Time=24.5/9.8=2.5 s
Answer:
Electric field, 
Explanation:
It is given that,
Mass of sphere, m = 2.1 g = 0.0021 kg
Charge, 
We need to find the magnitude of electric field that balances the weight of a plastic spheres. So,

a = g



or

Hence, the magnitude of electric field that balances its weight is
. Hence, this is the required solution.
Answer:
Horizontal component = 16.8 m/s
Vertical component = 46.0 m/s
Explanation:
If we denote the initial velocity by <em>v</em> and the angle above the horizontal by <em>θ</em>,
the horizontal component of this initial velocity is given by


The vertical component is given by

