Jacaranda Physics Prelim Questions (1 Viewer)

[FellowStudent]

* Which is larger in magnitude- the speed of a fly or the velocity of a fly? Explain.
* A car travelling east at a speed of 100m/s turns right to head south at the same speed. Has the car undergone an acceleration? Explain (perhaps with the aid of a diagram)

Cheers!

 

[1729]

* Which is larger in magnitude- the speed of a fly or the velocity of a fly? Explain.
* A car travelling east at a speed of 100m/s turns right to head south at the same speed. Has the car undergone an acceleration? Explain (perhaps with the aid of a diagram)

Cheers!

Q1. Aren't they equal? The magnitude of velocity is speed
Q2. There has been a change in direction and therefore a change in velocity. I think a change in velocity indicates an acceleration

 

[pikachu975]

* Which is larger in magnitude- the speed of a fly or the velocity of a fly? Explain.
* A car travelling east at a speed of 100m/s turns right to head south at the same speed. Has the car undergone an acceleration? Explain (perhaps with the aid of a diagram)

Cheers!

2. Turning around a bend means it experiences a centripetal acceleration hence centripetal force, Fc = mv^2 / r

 

[Fizzy_Cyst]

* Which is larger in magnitude- the speed of a fly or the velocity of a fly? Explain.
* A car travelling east at a speed of 100m/s turns right to head south at the same speed. Has the car undergone an acceleration? Explain (perhaps with the aid of a diagram)

Cheers!

1. Depends if it is instantaneous or average and whether there has been a change in direction. Assuming that it is linear motion and the fly does not change direction, then both magnitudes would be equal whether average or instantaneous.
If the fly changes direction throughout its flight, then magnitude of average speed would be greater than magnitude of average velocity.
If talking about instantaneous, both magnitudes are equal.

2. Yes, acceleration is defined as change in velocity divided by time taken. Velocity is a vector, therefore has magnitude and direction, seeing as direction has changed, velocity has changed, therefore car has experienced an acceleration.
Best to illustrate using a vector diagram showing final vector, negative of initial vector and then the resultant (which is change in velocity)

Btw, that's a pretty fast car

 

[Fizzy_Cyst]

2. Turning around a bend means it experiences a centripetal acceleration hence centripetal force, Fc = mv^2 / r

Only true if the turn forms an arc! If not circular, then not centripetal.