The source of heart for a (an) close system is electricity.
The answer to this question is Helium
Answer:
The acceleration is 
Explanation:
From the question we are told that
The lift up speed is 
The distance covered for the take off run is 
Generally from kinematic equation we have that

Here u is the initial speed of the aircraft with value 0 m/ s give that the aircraft started from rest
So

=> 
Answer:
t = 8.45 sec
car distance d = 132.09 m
bike distance d = 157.08 m
Explanation:
GIVEN :
motorcycle is 25 m behind the car , therefore distance need to covered by bike to overtake car is 25+ d, when car reache distance d at time t
for car
by equation of motion

u = 0 starting from rest


for bike


equating time of both

solving for d we get
d = 132 m
therefore t is

t = 8.45 sec
each travelled in time 8.45 sec as
for car

d = 132.09 m
fro bike

d = 157.08 m
Answer: 0.04139m
Explanation:
First, we need to calculate the weight of the man which will be:
Weight = mass × acceleration due to gravity
Weight = mg
Weight = 92.5 × 9.8
Weight = 906.5N
Then, we calculate the force which will be:
F = kx
mg = kx
x = mg/k
x = 906.5/21900
x = 0.04139m.
The spring stretched for 0.04139m.