Answer:
When a particle or a system of particles move in a system where no external force acts, then the total linear momentum of the particle system remains constant.
Explanation:
Given data:
Total mass of the skateboarder, 
Mass of the friend, 
Initial velocity of the skateboarder, 
Initial velocity of the the friend, 
Let the new velocity of the skateboarder when his friend jumps be 
.
From the conservation law of linear momentum,
Answer:
Periodic
Explanation:
A periodic (or repetitive) wave has continuously repeating pattern with characteristics such as amplitude, wavelength and frequency. In a periodic wave, a series of pulses that are evenly timed would be created. In other words, the wave pattern in a periodic wave repeats at regular intervals.
An example of a periodic wave is the sound from the strings of a violin.`
Answer:
67.5
Explanation:
The plane accelerates at 2.7m/s,^2
Time is 25 seconds
The velocity can be calculated as follows
= 25×2.7
= 67.5
Hence the speed f the plane is 67.5
"physical science" is a branch of science that is based on practical tests and explanations of the different phenomena. It is based on scientific evidence and tests/experiments.
Some of the branches that are based on physical science are:
1- Astronomy
2- Electronics
3- Engineering
4- Radiology
