When they say use energy, you want to use
Total energy = potential energy + kinetic energy = mgh + 1/2mv²
I assume you mean 200 g ball,
so, we know the total distance traveled is going to be 13 - 1.3 = 11.7 m
If the ball just makes it to the top ( 13 m ) , then the ball will stop moving and the kinetic energy will be 0,
therefore, the potential energy at the top will be the total energy of the system = mgh
from this, we say that mgh = 1/2mv² solve for v
<span>
v = sqrt (2gh) = 15.2 m/s </span>
- Mass=m=142kg
- Acceleration=a=30m/s
- Force=F
Using Newton's second law



It is customary to work in SI units.
Calculate the volume of the concrete.
V = 3.7*2.1*5.8 cm³ = 45.066 cm³ = 45.066 x 10 ⁻⁶ m³
The mass is 43.8 g = 43.8 x 10⁻³ kg
The density is mass/volume.
Density = (43.8 x 10⁻³ kg)/(45.066 x 10⁻⁶ m³) = 971.9 kg/m³
Answer: 971.9 kg/m³
So we want to know how can we detect infrared rays without an instrument. Infrared rays or heat, are a part of electromagnetic spectrum. We have specialized nerve cells in our skin called thermoreceptors that can detect differences in temperature that are produced by infrared part of EM spectrum.