Answer:
630.75 j
Explanation:
from the question we have the following
total mass (m) = 54.5 kg
initial speed (Vi) = 1.4 m/s
final speed (Vf) = 6.6 m/s
frictional force (FF) = 41 N
height of slope (h) = 2.1 m
length of slope (d) = 12.4 m
acceleration due to gravity (g) = 9.8 m/s^2
work done (wd) = ?
- we can calculate the work done by the boy in pushing the chair using the law of law of conservation of energy
wd + mgh = (0.5 mVf^2) - (0.5 mVi^2) + (FF x d)
wd = (0.5 mVf^2) - (0.5 mVi^2) + (FF x d) - (mgh)
where wd = work done
m = mass
h = height
g = acceleration due to gravity
FF = frictional force
d = distance
Vf and Vi = final and initial velocity
wd = (0.5 x 54.5 x 6.9^2) - (0.5 x 54.5 x 1.4^2) + (41 x 12.4) - (54.5 X 9.8 X 2.1)
wd = 630.75 j
Answer:7.93 m/s
Explanation:
Given
mass of ball 
Mass of hanging ball 
Length of string 
Maximum angle turned 
is the initial velocity of ball 1 and 0 is the initial velocity of ball 2
For Perfectly elastic final velocity of ball 1 and 2 is given by


where
and
are the velocity of 1 and 2 before collision
thus 



By energy conservation on second ball we get
Kinetic energy=Potential Energy




thus 
Answer: barometer
Explanation: An instrument that measures air pressure is called a barometer. One of the first barometers was developed in the 1600s. The original instrument had mercury in the small basin, with an upside down glass tube placed in the mercury.
We will define the Total mass to calculate the force, so our values are:
Total Mass 
The Weight is,

Through the hook's Law we calculate X.
, where x is the lenght of compression and K the Spring constant.
We don't have a K-Spring, but we can assume a random value (or simply let the equation in function of K)

I assume a value of 

Answer:
The induced current is 
Explanation:
From the question we are told that
The number of turns is
The cross-sectional area is 
The initial magnetic field is 
The magnetic field at time = 1.02 s is 
The resistance is 
The induced emf is mathematically represented as

The negative sign tells us that the induced emf is moving opposite to the change in magnetic flux
Here
is the change in magnetic flux which is mathematically represented as

Where dB is the change in magnetic field which is mathematically represented as

substituting values


Thus


So


The induced current i mathematically represented as

substituting values

