A ball is dropped from a 300.0m canyon ledge. How long would it take for the ball to hit the ground, ignoring air resistance? How far has it fallen after 3.0s?
a) 7.75s; 153.75m
b) 7.75s; 300.0m
c) 5.45s; 300.0m
d) 5.45s; 153.75m

Respuesta :

Answer:

To solve this problem, we can use the equations of motion under constant acceleration due to gravity. Since the ball is dropped, its initial velocity is 0 m/s.

Time to hit the ground (ignoring air resistance):

We can use the equation for the displacement (s) of an object under constant acceleration:

=

+

1

2

2

s=ut+

2

1

at

2

Where:

s is the displacement (300.0 m, in this case)

u is the initial velocity (0 m/s)

a is the acceleration due to gravity (approximately

9.81

m/s

2

9.81m/s

2

)

t is the time taken

Rearranging the equation for

t, we get:

=

2

t=

a

2s

Substituting the given values:

=

2

×

300.0

m

9.81

m/s

2

t=

9.81m/s

2

2×300.0m

600.0

m

9.81

m/s

2

t≈

9.81m/s

2

600.0m

61.1737

s

2

t≈

61.1737s

2

7.82

s

t≈7.82s

So, it would take approximately 7.82 seconds for the ball to hit the ground, ignoring air resistance.

Distance fallen after 3.0 seconds:

We can use the equation:

=

+

1

2

2

s=ut+

2

1

at

2

Where:

s is the displacement (which we want to find)

u is the initial velocity (0 m/s)

a is the acceleration due to gravity (approximately

9.81

m/s

2

9.81m/s

2

)

t is the time taken (3.0 seconds)

Substituting the given values:

=

0

×

3.0

+

1

2

×

9.81

×

(

3.0

)

2

s=0×3.0+

2

1

×9.81×(3.0)

2

=

0

+

1

2

×

9.81

×

9.0

s=0+

2

1

×9.81×9.0

=

0

+

1

2

×

88.29

s=0+

2

1

×88.29

=

0

+

44.145

s=0+44.145

=

44.145

m

s=44.145m

So, after 3.0 seconds, the ball has fallen approximately 44.145 meters.

Explanation:

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