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Physics As level

Luj99

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T=2π squareroot(1/g)
T=2π squareroot(m/k)

Pls help me fast

Do they all have the same units?

Reply 3

coupezaj

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Reply 4

Luj99

Original post by Kyx

Do they all have the same units?

No they don't

Reply 5

Luj99

Pls hurry guys, I need to complete it tomorrow. (The symbols have their usual meaning) for example m=mass T=seconds

Reply 6

Joinedup

have you been taught anything about this?

for these dimensional homogeneity questions you have to think in terms of the dimension rather than the unit system...
L is length
T is time (not seconds, seconds is the SI unit for measuring time)
M is mass

so for
a) T=2π (l/g)^1/2

you can kick out the 2π immediately because it's dimensionless

T=(l/g)^1/2
T²=l/g

now start to put it into the dimensional notation
the dimension of T is T
the dimension of l is L
the dimension of g in basic dimensions (and the dimension of any acceleration) is L T^-2 (might help to think about the units acceleration is measured in)

so in dimensional notation we've got
T²=L / L T^-2

cancel the Ls
T²=1/T^-2
so
T²=T²
T=T ...which is what we're asked for.

NB not all constants are dimensionless so you've got to include the dimensions of (for example) spring constants & the gravitational constant.