Question

Divers in Acapulco dive from a cliff that is 65 m high. If the rocks

Answer 1

Answer:

Cool question! First step is to find the time taken to fall

57

m

, then to find the horizontal velocity needed to cover

24

m

in that time. In this case the answer is

7.0

m

s

−

1

.

Explanation:

This is a less typical projectile motion question, but it's still projectile motion. This means the horizontal and vertical directions can be considered separately. We assume that the initial vertical velocity,

u

y

=

0

m

s

−

1

, and we are trying to find the required initial horizontal velocity,

u

x

.

To find the time taken to fall

57

m

:

s

=

u

t

+

1

2

a

t

2

Since

u

=

0

, we can rearrange this to:

t

=

√

2

s

a

=

√

2

⋅

57

9.8

=

3.41

s

The horizontal velocity will be constant (ignoring air resistance), so to cover

24

m

in

3.41

s

will be given by:

v

=

s

t

→

u

x

=

24

3.41

=

7.0

m

s

−

1

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