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3 years ago

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An advertisement for a new fish food claims that lab studies show that fish grew three inches in three weeks while eating the fo

od. Travis wondered if the food was worth the extra cost. To evaluate the claim in the advertisement, Travis should

1 answer:

Varvara68 [4.7K]3 years ago

6 0

Check the data for the control group to see how much the fish grew without the new food.

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A calorimeter directly measures ______ in order to calculate ______. (1 point)

Aneli [31]

The complete sentence is:

A calorimeter directly measures changes in temperature in order to calculate specific heat.

In fact, the amount of energy acquired/released by a substance is directly proportional to its change in temperature due to the equation

$Q=mC_s \Delta T$

where Q is the amount of energy, m is the mass of the substance, Cs is the specific heat of the substance and $\Delta T$ is the change in temperature. Therefore, by knowing Q, m and by measuring the change in temperature, it is possible to calculate Cs, the specific heat capacity of the substance.

4 0

2 years ago

Read 2 more answers

Superman is supposed to leap tall buildings in a single bound. Suppose that he obeys the normal laws of physics in this feat. Es

lys-0071 [83]

Answer:

31.32 m/s

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

a = Acceleration due to gravity = 9.81 m/s²

Let us assume the height of the Disque hall is 50 m

$v^2-u^2=2as\\\Rightarrow -u^2=2as-v^2\\\Rightarrow u=\sqrt{v^2-2as}\\\Rightarrow u=\sqrt{0^2-2\times -9.81\times 50}\\\Rightarrow u=31.32\ m/s$

In order to make the jump Superman's initial velocity must be greater than or equal to 31.32 m/s

6 0

3 years ago

A sky diver with a mass of 70kg jumps from an aircraft. The aerodynamic drag force acting on the sky diver is known to be Fd=kV^

xeze [42]

Answer:

$v_{max}=52.38\frac{m}{s}$

$v_{100}=33.81$

Explanation:

the maximum speed is reached when the drag force and the weight are at equilibrium, therefore:

$\sum{F}=0=F_d-W$

$F_d=W$

$kv_{max}^2=m*g$

$v_{max}=\sqrt{\frac{m*g}{k}} =\sqrt{\frac{70*9.8}{0.25}}=52.38\frac{m}{s}$

To calculate the velocity after 100 meters, we can no longer assume equilibrium, therefore:

$\sum{F}=ma=W-F_d$

$ma=W-F_d$

$ma=mg-kv_{100}^2$

$a=g-\frac{kv_{100}^2}{m}$ (1)

consider the next equation of motion:

$a = \frac{(v_{x}-v_0)^2}{2x}$

If assuming initial velocity=0:

$a = \frac{v_{100}^2}{2x}$ (2)

joining (1) and (2):

$\frac{v_{100}^2}{2x}=g-\frac{kv_{100}^2}{m}$

$\frac{v_{100}^2}{2x}+\frac{kv_{100}^2}{m}=g$

$v_{100}^2(\frac{1}{2x}+\frac{k}{m})=g$

$v_{100}^2=\frac{g}{(\frac{1}{2x}+\frac{k}{m})}$

$v_{100}=\sqrt{\frac{g}{(\frac{1}{2x}+\frac{k}{m})}}$ (3)

$v_{100}=\sqrt{\frac{9.8}{(\frac{1}{2*100}+\frac{0.25}{70})}}$

$v_{100}=\sqrt{\frac{9.8}{(\frac{1}{200}+\frac{1}{280})}}$

$v_{100}=\sqrt{\frac{9.8}{(\frac{3}{350})}}$

$v_{100}=\sqrt{1,143.3}$

$v_{100}=33.81$

To plot velocity as a function of distance, just plot equation (3).

To plot velocity as a function of time, you have to consider the next equation of motion:

$v = v_0 +at$

as stated before, the initial velocity is 0:

$v =at$ (4)

joining (1) and (4) and reducing you will get:

$\frac{kt}{m}v^2+v-gt=0$

solving for v:

$v=\frac{ \sqrt{1+\frac{4gk}{m}t^2}-1}{\frac{2kt}{m} }$

Plots:

5 0

3 years ago

The focal length of a concave lens 13.3 cm.Calculate its power.

cricket20 [7]

Explanation:

Formula for finding power : 1/f

Substitution of values:

1 /13.3 = 0.07518 cm

Please mark it as Brainliest!

4 0

2 years ago

You are asked to design a spring that will give a 1020 kg satellite a speed of 2.25 m/s relative to an orbiting space shuttle. Y

julsineya [31]

Answer:

(a) 2.45×10⁵ N/m

(b) 0.204 m

Explanation:

Here we have that to have a velocity of 2.25 m/s then the relationship between the elastic potential energy of the spring and the kinetic energy of the rocket must be

Elastic potential energy of the spring = Kinetic energy of the rocket

$\frac{1}{2} kx^2 = \frac{1}{2} mv^2$

Where:

k = Force constant of the spring

x = Extension of the spring

m = Mass of the rocket

v = Velocity of the rocket

Therefore,

$\frac{1}{2} kx^2 = \frac{1}{2} \times 1020 \times 2.25^2$

or

$kx^2 = 1020 \times 2.25^2 = 10,226.25\\So \ that \ the \ force \ on \ the \ satellite\ kx = \frac{10226.25}{x}$

(b) Since the maximum acceleration is given as 5.00×g we have

Maximum acceleration = 5.00 × 9.81 = 49.05 m/s²

Hence the force on the rocket is then;

Force = m×a = 1020 × 49.05 = ‭50,031 N

$kx = \frac{10226.25}{x} = 50031 \ N$

Therefore,

$x = \frac{10226.25}{ 50031} = 0.204 \ m$

(a) From which

$k = \frac{10226.25}{x^2} = \frac{50031}{x} = \frac{50031}{0.204} = 244,772.13 \ N/m$ or

Force constant of the spring, k = 2.45×10⁵ N/m.

6 0

3 years ago