Qn on Acceleration

wishboy SG

From Unity Sec Prelim'07,

What must be changing when a body is accelerating uniformly?

A) the speed of the body

B) the mass of the body

C) the force acting on the body

D) the velocity of the body

Ans: A

Isn't option D a possible answer too?

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From SAP TYS,

What must change when a body is accelerating?

A) the force acting on the body

B) the mass of the body

C) the speed of the body

D) the velocity of the body

Year 2002 ans: D
Year 2005 ans: A

So which should be the correct answer? My guess is D since acceleration is the rate of change of velocity.

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Random qn,

When a car is travelling at constant speed around a circular track, is it accelerating, decelerating, or not at all?

eagle SG

What must be changing when a body is accelerating uniformly?
A) the speed of the body
B) the mass of the body
C) the force acting on the body
D) the velocity of the body

Uniform acceleration means accelerating in the same direction at the same magnitude
One example of why d cannot be is that of a circular motion. The acceleration changes direction at every point.

What must change when a body is accelerating?

A) the force acting on the body

B) the mass of the body

C) the speed of the body

D) the velocity of the body

D is correct, A is wrong
Because a body can be accelerating, but the force acting on it might not change.

wishboy SG

Uniform acceleration means accelerating in the same direction at the same magnitude
One example of why d cannot be is that of a circular motion. The acceleration changes direction at every point.

Ok, so am I right to say that the body is moving in the same direction with an increasing speed?

If so, won't the velocity also be changing as there is a rate of change of displacement?

eagle SG

Ok, so am I right to say that the body is moving in the same direction with an increasing speed?

If so, won't the velocity also be changing as there is a rate of change of displacement?

my mistake

you are right.

I think D is a better answer than A.

It can also be changing direction in a circular motion. This is called angular acceleration, also a form of acceleration, where the direction of velocity is changing, but magnitude (and hence speed) remains the same.

davidche SG

can i conclude that acc. has to do with velocit

What must change when a body is accelerating?

A) the force acting on the body

B) the mass of the body

C) the speed of the body

D) the velocity of the body

thus cant be c

wishboy SG

my mistake

you are right.

I think D is a better answer than A.

oh ok

hmm... angular acceleration is smth new to me

thanks