Friday, June 26, 2009

How to find the magnetic force on and acceleration

Topic:-Magnetic force on and Acceleration

A magnetic field is a vector field which surrounds magnets and electric currents, and is detected by the force it exerts on moving electric charges and on magnetic materials and acceleration is the change in velocity over time.

Let's see how these two works along with each other in the following problem.

Question:-

If we have an 8.2A current running through a 0.012meter wire, with a magnetic fields strength of 1.2T, what would be the direction of the force and what would be the acceleration of the 0.32kg wire? Find the net force, direction and acceleration?

ANSWER:

This physics help explanation is based direction of force.

Net force=0.11808N, Acceleration=.01296*1031 m/sec2

Here,

I=8.2A

Mass= 0.32kg

L =0.012meter

B=1.2T

F=BIl sinθ, here θ=90, so sinθ=1

Force on a current carrying wire of length l is=0.11808N

F is perpendicular to both E and B

Acceleration=F/m= .01296*1031 m/sec2



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Wednesday, June 17, 2009

Problems on speed and Velocity

Topic:Acceleration

Acceleration is the change in velocity ,which refers to "the rate at which an object changes its position" over time.

Here is a some simple problems on acceleration,which helps you to find speed of a moving object.


  1. A bicyclist starts down a ramp, traveling at a speed of 2.8m/s, and then accelerates at 0.25m/s^2 for 18s. What is his speed at the bottom of the ramp

ANSWER: 7.3m/sec

V initial=2.8m/s

Acceleration=0.25m/s^2

Time=18s.

V final=?

V final= V initial+ Acceleration* Time =2.8+ (0.25*18) = 7.3m/sec


2.A race car traveling at 55m/s, slows down to 9m/s with an acceleration of-9.2m/s^2 to take a corner. How long does it take the race car to slow down?

ANSWER: 5 seconds

V initial=55m/s

V final=9m/s

Acceleration=-9.2m/s^2

Acceleration= V final- V initial/ Time

Time=9m/s-55m/s/9.2m/s^2=5 seconds


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