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d1i1m1o1n [39]
2 years ago
15

Tim sets up an experiment with 3 groups of runners. Group 1 smokes 1 pack per day. Group 2 smokes 2 packs per day. Group 3 smoke

s 3 packs per day. Tim does a study to determine whether or not cigarette smoking decreases speed in track runners. After 1 month, Tim measures the average 40 yard dash time for each group and finds that group 3 was the slowest, 2 was in the middle, and 1 was the fastest. He concludes that cigarette smoking decreases speed, but this is not necessarily correct. What was wrong with his experiment? A) Tim measured more than one independent variable. B) Tim did not have a dependent variable. C) Tim did not use a control group. D) Tim did not have a hypothesis.
Physics
1 answer:
Anna007 [38]2 years ago
5 0

Answer:

Tim did not use a control group

Explanation:

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If g were 15 instead of 9.81, what would your quads look like?
Jlenok [28]

Answer:

Quads will have more energy

Explanation:

If the acceleration due to gravity increases from 9.81 to 15, then the velocity will increase as the rate of changing velocity i.e acceleration has increased from 9.81 to 15 m/s^2

With increase of velocity, the energy and force will also increase. Hence, the squad will require/have higher energy.

5 0
2 years ago
A car accelerates from rest at a constant rate of 1.6
SIZIF [17.4K]

Answer:

8m/s

Explanation:

it says that its at a constant rate of 1.6 that means it doesn't change and the car accelerates for 5 seconds so 1.6 X 5 which is 8

7 0
2 years ago
A stationary block resting on the ground is pulled up with a tension force of 100N, but does not leave the ground.
tekilochka [14]

Answer:

The normal force the ground exerts on the block, F = -300 N

Explanation:

Given data,

The block pulled up with a tension force, T = 100 N

The weight of the block, W = 300 N

The weight of the block is due to the force of attraction of gravitation.

The surface exerts a force that is equal and opposite to the force acting on the block due to gravitation.

The weight of the block,

                                  W = mg

                                          300 N

The normal force the ground exerts on the block,

                                  F = - mg

                                    = - 300 N

Hence, the normal force the ground exerts on the block, F = -300 N

6 0
3 years ago
Traveling waves propagate with a fixed speed usually denoted as v (but sometimes c). The waves are called __________ if their wa
Snezhnost [94]

Answer:

Periodic.

Explanation:

Electromagnetic waves is a propagating medium used in all communications device to transmit data (messages) from the device of the sender to the device of the receiver.

Generally, the most commonly used electromagnetic wave technology in telecommunications is radio waves.

Radio waves can be defined as an electromagnetic wave that has its frequency ranging from 30 GHz to 300 GHz and its wavelength between 1mm and 3000m. Therefore, radio waves are a series of repetitive valleys and peaks that are typically characterized of having the longest wavelength in the electromagnetic spectrum.

Basically, as a result of radio waves having long wavelengths, they are mainly used in long-distance communications such as the carriage and transmission of data.

Generally, a fixed speed is used for the propagation of traveling waves and this speed is usually denoted with the variable "v" or sometimes "c."

Furthermore, if the waveform of a traveling wave is repeated every time at specific intervals T, it is referred to as periodic wave.

Mathematically, the period of a traveling wave is given by the formula;

Period = \frac {1}{T}

Where;

T is the time measured in seconds.

5 0
2 years ago
A stone is thrown vertically into the air at an initial velocity of 96 ft/s. On Mars, the height s (in feet) of the stone above
vladimir1956 [14]

Answer:

240 ft

Explanation:

t = Time taken

u = Initial velocity = 96 ft/s

v = Final velocity

s = Displacement

a = Acceleration = 12 m/s² on Mars 32 ft/s² on Earth negative due to upward direction

Mars

s=ut+\frac{1}{2}at^2\\\Rightarrow s=96\times t+\frac{1}{2}\times -12\times t^2\\\Rightarrow s=96t-6t^2\ ft

Earth

s=ut+\frac{1}{2}at^2\\\Rightarrow s=96\times t+\frac{1}{2}\times -32\times t^2\\\Rightarrow s=96t-16t^2\ ft

Differentiating the first equation with respect to time we get

\frac{ds}{dt}=96-12t

Equating with zero

0=96-12t\\\Rightarrow t=\frac{96}{12}=8\ s

Differentiating the second equation with respect to time we get

\frac{ds}{dt}=96-32t

Equating with zero

0=96-32t\\\Rightarrow t=\frac{96}{32}=3\ s

Applying the time taken to the above equations, we get

s=96t-6t^2\ ft\\\Rightarrow s=96\times 8-6\times 8^2\\\Rightarrow s=384

s=96t-16t^2\\\Rightarrow s=96\times 3-16\times 3^2\\\Rightarrow s=144

Difference in height = 384-144 = 240 ft

The stone will travel 240 ft higher on Mars

6 0
2 years ago
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