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2 years ago

A penny is dropped from the top of a tower. It hits the ground below after 2.5 s. How tall was the tower?

Physics

1 answer:

pychu [463]2 years ago

3 0

Answer:

C. 30.6m

Explanation:

To find the height of the tower, we are to use Newtons law of motion to solve this problem. Since the penny is falling from the top of the tower, it is acted by the acceleration due to gravity. The formula to be used is:

$H=ut+\frac{1}{2}gt^2$

Where H is the height of the tower, t is the time taken to hit the ground, u is the initial velocity and g is the acceleration due to gravity.

Given that, t = 2.5 s, g =9.8 m/s², u = 0 m/s (at the top of tower)

$H=ut+\frac{1}{2}gt^2\\\\H=0(2.5)+ \frac{1}{2}(9.8)(2.5)^2\\\\H=30.6\ m$

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Vladimir79 [104]

Answer:

60 meters

Explanation:

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2 years ago

Which statements describe using genetic factors to influence the growth of organisms? Select the three (3) that apply.

Damm [24]

Answer:

- increasing use of hybrid crops

- altering genes in DNA to create new plants

- developing disease or pest resistant crops

Explanation:

The use of genetic factors to influence the growth of a plant encompasses manipulating the genetic constituent (gene) of such plant.

For example,

- Increasing use of hybrid crops entails mating two pure bred plants based on a gene of interest responsible for a particular trait, to form a hybrid.

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- developing disease or pest resistant crops means that the genetic make up of such plant has been modified to be resistant to pest/disease.

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2 years ago

To cross the river a swimmer chooses the direction minimizing the amount of time spent in the water. The swimmer swims at a cons

Lynna [10]

Answer:

304 meters downstream

Explanation:

The given parameters are;

The speed of the swimmer = 2.00 m/s

The width of the river = 73.0 m

The speed of the river = 8.00 m/s

Therefore;

The direction of the swimmer's resultant velocity = tan⁻¹(8/2) ≈ 75.96° downstream

The distance downstream the swimmer will reach the opposite shore = 4 × 73 = 304 m downstream

The distance downstream the swimmer will reach the opposite shore = 304 m downstream

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2 years ago

A child on a tricycle is moving at a speed of 1.40 m/s at the start of a 2.25 m high and 12.4 m long incline. The total mass is

goblinko [34]

Answer:

The work done by the child as the tricycle travels down the incline is 416.96 J

Explanation:

Given;

initial velocity of the child, $v_i$ = 1.4 m/s

final velocity of the child, $v_f$ = 6.5 m/s

initial height of the inclined plane, h = 2.25 m

length of the inclined plane, L = 12.4 m

total mass, m = 48 kg

frictional force, $f_k$ = 41 N

The work done by the child is calculated as;

$\Delta E_{mech} = W - f_{k} \Delta L\\\\W = \Delta E_{mech} + f_{k} \Delta L\\\\W = (K.E_f - K.E_i) + (P.E_f - P.E_i) + f_{k} \Delta L\\\\W = \frac{1}{2} m(v_f^2 - v_i^2) + mg(h_f - h_i) + f_{k} \Delta L\\\\W = \frac{1}{2} \times 48(6.5^2 - 1.4^2) + 48\times 9.8(0-2.25) + (41\times 12.4)\\\\W = 966.96 \ - \ 1058.4 \ + \ 508.4\\\\W = 416.96 \ J$

Therefore, the work done by the child as the tricycle travels down the incline is 416.96 J

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2 years ago

The “Big Bang” is an example of what type of scientific statement? A. A law B.a hypothesis C. A theory D. An equation

Ugo [173]

Answer:

theory

Explanation:

that's why it's called the Big Bang Theory

6 0

2 years ago

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