Answer:
u need to make sure that comparison is = to shapes and then find the shapes sizes and add them
Answer:
Lilly's speed is two times John's speed.
Explanation:
m = Mass
a = Acceleration
t = Time taken
u = Initial velocity
v = Final velocity
The force they apply on each other will be equal




Hence, Lilly's speed is two times John's speed.
A.draw in the forces .Use the scale 1cm =10n of force
Answer:
Amount of radioactive particles left after 60 years = 100 particles.
Explanation:
Amount of radioactive particles before 60 years = 400
Amount of radioactive particles present today = 200
That is radio active particles reduced to half. That is 60 years is half life of this radio active material.
After 60 years this 200 radio active particles will reduce to half.
Amount of radioactive particles left after 60 years = 0.5 x 200 = 100 particles.
Answer: a) 23 m/s
Explanation: In order to solve this problem we have to consider the circular movement where the friction force change de direcion of the velocty to keep a circular trajectory.
By using Second Newton law, we have:
F=m*acentripeta
μ*N= m*v^2/r where N ( equal to mg) is the normal force and μ is the coefficient of friction. r is the redius of the trajectory.
so
the maximun speed permited to keep a circular trajectory is calculated as:
v= (μ*r*g)^1/2=(0.65*80m*9.8 m/s^2)^1/2=22.57 m/s