but if the question like in this case didnt say anything about direction, how would you answer the question?
direction of acceleration is the same as the direction of the net force. that is the net force causing the object to move in the circular direction.
if i haven forget my physics, the centripetal force is pointing towards the centre of the circle while the velocity is at a tangent to the circle
siala. i dont think olvl requires so chim de la.
Originally posted by deteq:siala. i dont think olvl requires so chim de la.
got ar...nowsaday they like to set thinking questions. So instead of having so many calculations, they 'd rather ask stuff like direction.
they not so evil de la. i never even heard of such terms centripetal force. but maybe i lousy. i combine science nia.
Originally posted by gunner77:3(a) a car travels round a circular track at a constant speed of 40km/h
explain why the car's velocity is not constant?
3(b) is the car accelerating? explain your answer
Velocity, as tinny has said, consist of magnitude and direction.
Since the car is travelling in a circular path, it's direction of motion is constantly changing, i.e. one moment it is travelling south, the other east, north, west, etc... Always changing directions.
Hence velocity is not constant
The car is always accelerating towards the centre of the circular path, because there's a net centripetal force. :D
Originally posted by tinuviel07:if the direction of acceleration is same as velocity, then is acceleration. if the direction is opposite, then is deceleration.. eagle come explain lah
direction of acceleration is perpendicular to the velocity for this circular motion. :D
This acceleration serves to change the direction of the velocity in the circular path, not magnitude.
So is the car accelerating or decelerating when it runs at a constant SPEED in circles.
Originally posted by davidche:So is the car accelerating or decelerating when it runs at a constant SPEED in circles.
does it matter?
what is the actual definition of acceleration?
It is the rate of change of velocity. Deceleration merely has its magnitude negative of acceleration. In strict physics definitions, you don't really see the definition of deceleration
So to answer the question, the car is accelerating as the velocity is changing.
Correct! :D
1B) define the frequency of a wave.
3C) all electronmagnetic waves are transverse. what is the meaning of the term transverse?
anyone can help me?
Originally posted by gunner77:1B) define the frequency of a wave.
3C) all electronmagnetic waves are transverse. what is the meaning of the term transverse?
anyone can help me?
erm
1b) frequency is the number of cycles of the wave per second
3c) tranverse means the the motion of the particles are perpendicular to the direction of wave travel
Originally posted by gunner77:1B) define the frequency of a wave.
3C) all electronmagnetic waves are transverse. what is the meaning of the term transverse?
anyone can help me?
Frequency is the number of successive crests or troughs or any parts of the wave that passes through a point per sec.
transverse waves are waves which travel perpendicular to the vibration of particles that propogate the energy.
Lol very crude phrasing. I think the ans is in textbook.
Transverse waves:
Direction of vibration is perpendicular to the direction of the wave
Travels in a series of crests and troughs
thanks everyone !
another few more questions
2) the radiation that reaches earth from the sun is electromagnetic radiation.
state one way in which the components of the electromagnetic spectrum are different.
Originally posted by gunner77:another few more questions
2) the radiation that reaches earth from the sun is electromagnetic radiation.
state one way in which the components of the electromagnetic spectrum are different.
frequency or wavelength
5c) at a speed of 40m/s, the driving force is 5200N. calculate the work done when the car travels 200m at this speed?
Originally posted by eagle:frequency or wavelength
huh?
Originally posted by gunner77:5c) at a speed of 40m/s, the driving force is 5200N. calculate the work done when the car travels 200m at this speed?
work done = f*d = 5200 * 200 = 1040000J
Originally posted by gunner77:
huh?
each individual component of the electromagnetic spectrum varies in terms of frequency and wavelength
Originally posted by eagle:work done = f*d = 5200 * 200 = 1040000J
the answer is 1.04 MJ
wat the hell is MJ?
Originally posted by eagle:each individual component of the electromagnetic spectrum varies in terms of frequency and wavelength
the answer is "they have different wavelengths"
ohh i understand liao
Originally posted by gunner77:
the answer is 1.04 MJwat the hell is MJ?
MJ is mega joules
it is 10^6 joules
so 1.04 * 10^6 J = 1040000 J