Answer: 
beta particles
Explanation:
Given mass = 14.0 g
Molar mass = 137 g/mol
According to avogadro's law, 1 mole of every substance weighs equal to its molecular mass and contains avogadro's number 
of particles.
1 mole of cesium contains atoms =
0.102 moles of cesium contains atoms = 
The relation of atoms with time for radioactivbe decay is:
Where 
=atoms left undecayed
= initial atoms
t = time taken for decay = 3 minutes
= half life = 30.0 years = 
minutes
The fraction that decays : 
Amount of particles that decay is = 
Thus beta particles are emitted by a 14.0-g sample of cesium-137 in three minutes.
I cant do all but I can do number 4
When force moves ur leg u start skatin and when that happenes ur using a lot of force to move
Answer:
A machine in which work input equals work output. energy can be used to do work, work can be used to transfer energy. The change in the kinetic energy of an object is equal to the net work done on the object.
hope this helps
Answer:
The work done by the child as the tricycle travels down the incline is 416.96 J
Explanation:
Given;
initial velocity of the child, 
= 1.4 m/s
final velocity of the child, 
= 6.5 m/s
initial height of the inclined plane, h = 2.25 m
length of the inclined plane, L = 12.4 m
total mass, m = 48 kg
frictional force, 
= 41 N
The work done by the child is calculated as;
Therefore, the work done by the child as the tricycle travels down the incline is 416.96 J
