Question

jack be nimble jack be quick jack jumped over the candlestick with a velocity of 5.0 m/s at an angle of 30.0 degrees to horizontal. did jack burn his feet on the 0.25-m-high candle?

Answer 1

Answer:

No

Explanation:

The vertical component of Jack's initial velocity is:

5.0

⋅

sin

30

∘

=

5.0

⋅

1

2

=

2.5

m/s

With gravitational acceleration

9.8

m/s

2

, he will reach the highest point of his trajectory after:

2.5

9.8

≈

0.255

s

The average vertical component of his velocity in that

0.255

s

will be:

1

2

⋅

2.5

=

1.25

m/s

So the highest point of his trajectory will be:

0.255

⋅

1.25

≈

0.32

m

So he will pass approximately

7

cm

above the top of the candle.

The horizontal component of his velocity will be a constant:

5.0

⋅

cos

30

∘

=

5.0

⋅

√

3

2

≈

4.33

m/s

So Jack's trajectory will be substantially longer than it is high and he will spend little time anywhere near above the candle.