Answer:
b. less than w.
Explanation:
In this question, the application of length contraction is what helps us come to our conclusion. When an object moves very fast (relative to the observer), the length of the object seems to be smaller than it actually is (again, for the observer).
This is supported by the length contraction equation below:
L = 
Here, L is the observed length
is the original length of the object
v is the relative speed between the object and the observer
and c is the speed of light
Using this equation, we can see that as the speed between the object and the observer is increased to be close to that of light, the square root in the equation gives us values less than 1.0
This effectively decreases the length that is observed.
The distance is 9.0 meters because that's how far the person ran. The displacement is 2.4 meters North because displacement is a speed AND direction. Basically you're calculating how far you are from where you started.
Answer:
Explanation:
For circular path in magnetic field
mv² / R = Bqv ,
m is mass , v is velocity , R is radius of circular path , B is magnetic field , q is charge on the particle .
a )
R = mv / Bq
If v is changed to 2v , keeping other factors unchanged , R will be doubled
b )
magnitude of acceleration inside field
= v² / R
= Bqv / m
As v is doubled , acceleration will also be doubled
c )
If T be the time inside the magnetic field
T = π R / v
= π / v x mv / Bq
= π m / Bq
As is does not contain v that means T remains unchanged .
d )
Net force acting on electron
= m v² / R = Bqv
Net force = Bqv
As v becomes twice force too becomes twice .
So a . b , d are correct answer.
Answer:
the work done by gravity on the boy is 604.62 J
Explanation:
Given;
distance the boy slides, d = 3 m
angle of inclination of the playground, θ = 40⁰
mass of the boy, m = 32 kg
The vertical height, h, above the ground through which the boy falls represents the height of the triangle which is the opposite side.
The distance through which the boy slides, d, represents the hypotenuse side of the right triangle.

The work done by gravity on the boy is calculated as;
W = P.E = mgh
= 32kg x 9.8m/s² x 1.928m
= 604.62 J
Therefore, the work done by gravity on the boy is 604.62 J