Question

An arrow travelling at 45 m/s strikes
and embeds itself in a 450 g apple which is
initially at rest. They move off horizont
ally at 12 m/s after impact. What is the
mass of the arrow?

Answer 1

i did m(45)+(0)(450)=(450)(12), what am i doing wrong ? @Michele_Laino

Answer 2

the right equation, is:
\[\Large m \times 45 + 0 \times 450 = \left( {m + 450} \right) \times 12\]

Answer 3

i havve to find 1 m so why is their two

Answer 4

?

Answer 5

since after the impact, te arrow and the apple are ambedded each other, so their momentum is:
\[\Large \left( {m + 450} \right) \times 12\;\frac{{{\text{grams}} \times {\text{m}}}}{{{\text{sec}}}}\]

Answer 6

after a simple computation, we get:
\[\Large m = \frac{{450 \times 12}}{{33}} = ...{\text{grams}}\]

Answer 7

what happned to the other "m"?

Answer 8

when we simplify it ?

Answer 9

@Michele_Laino

Answer 10

the mass of apple is 450 grams

Answer 11

i mean the m on the left side

Answer 12

when we solve for one variable you can't have 2

Answer 13

here are more steps:
\[\Large \begin{gathered}
m \times 45 + 0 \times 450 = \left( {m + 450} \right) \times 12 \hfill \\
45m = 12m + 450 \times 12 \hfill \\
33m = 450 \times 12 \hfill \\
\end{gathered} \]

Answer 14

ohhh