Solving Two Physics Questions: Units of Velocity and Acceleration Equations

[MoreZitiPlease]

Homework Statement

Which of the following is not a unit of velocity?
A) m/s C) km/ms
B) m/N D) mm/ms

If an object starts from rest and travels a distance d in t sec, which of the following equations may be used to find its acceleration?
A) Vf = Vi + at C) d = Vi t + ½ at2
B) Vf2 = Vi2 +2ad D) d = ½ (Vf + Vi) t

Homework Equations

In problems

The Attempt at a Solution

Ok, for #1 I am going or answer B because I have never seen that before.

FOr the 2nd one, I amgoing to go with A.

AmI right?

 

[Bill Foster]

Homework Statement

Which of the following is not a unit of velocity?
A) m/s C) km/ms
B) m/N D) mm/ms

Only A is a unit of velocity.

If an object starts from rest and travels a distance d in t sec, which of the following equations may be used to find its acceleration?
A) Vf = Vi + at C) d = Vi t + ½ at2
B) Vf2 = Vi2 +2ad D) d = ½ (Vf + Vi) t

C

 

[Shooting Star]

Ok, for #1 I am going or answer B because I have never seen that before.

FOr the 2nd one, I amgoing to go with A.

AmI right?

Use some logic.

1. Velocity has dimension of distance/time. Which of them does not ultimately decompose into that?

2. Choice A doesn't even have 'd' in it. Which one has d and t and the initial velocity?

 

[catkin]

kilometers per millisecond and mmillimeters per millisecond may be very unusual units of velocity (more properly speed since direction is unstated) but they are units of speed.

 

[MoreZitiPlease]

Use some logic.

1. Velocity has dimension of distance/time. Which of them does not ultimately decompose into that?

2. Choice A doesn't even have 'd' in it. Which one has d and t and the initial velocity?

Damn, I am sorry.

Um

So #1 is B

and # 2 is C

?

 

[Shooting Star]

That's more like it!

 

[Marghk]

If an object starts from rest and travels a distance d in t sec, which of the following equations may be used to find its acceleration?
A) Vf = Vi + at C) d = Vi t + ½ at2
B) Vf2 = Vi2 +2ad D) d = ½ (Vf + Vi) t

C. Using one of the three laws of projectile motion.

It obviously can't be A as it doesn't have Distance in it. It can't be B because that doesn't have time in it and D doesn't even hold acceleration.

Therefore C is the right answer you would just need to re-arrange the equation to get a as a subject.