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3 years ago

22) A driver traveling at 80 km/h brakes her 2000 kg truck to stop for a red light. How much internal energy is produced

Physics

1 answer:

blsea [12.9K]3 years ago

3 0

Answer:

$E=4.9\times 10^5\ J$

Explanation:

Given that,

The speed of a driver, v = 80 km/h = 22.22 m/s

The mass of the truck, m = 2000 kg

We need to find how much internal energy is produced. The internal energy produced by a truck is its kinetic energy and it is given by :

$E=\dfrac{1}{2}mv^2\\\\E=\dfrac{1}{2}\cdot22.22^{2}\cdot2000\\\\E=493728.4\ J$

$E=4.9\times 10^5\ J$

So, $4.9\times 10^5\ J$ of internal energy is produced.

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In concave mirror, the size of image depends upon

irina1246 [14]

Answer:

The distance of the object placed on the principal axis from the concave mirror.

Explanation:

In a concave mirror, the nature of the image formed formed by the object placed in front of the mirror depends on the position of the object placed in from of the mirror. It all depends on the distance between the mirror and the object placed on the principal axis.

The closer the object is to the lens, the more larger or magnified the image formed will be. For example an object placed between the focal point and the pole of a concave produces a much larger image than an object placed beyond the centre of curvature of such mirror.

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3 years ago

Read 2 more answers

Vivian went on a bicycle trip through Germany with her family. One afternoon, she rode her bicycle along a long flat road at a c

natima [27]

d = distance traveled by her on her bicycle on a long flat road = 24 kilometer

t = time taken by her to travel distance "d" on her bicycle on a long flat road = 1.2 hours

v = average speed of vivian = ?

we know that average speed is given as

v = d/t

inserting the values in the above formula

v = 24 kilometer / 1.2 hour

v = 20 kilometer/hour

hence the correct choice is

C) 20 km/h

8 0

3 years ago

Based on the following equation, answer the questions below. ρ = (2γϕ + ψ)/rg where ρ [=] moles per cubic foot [mol/ft3] γ [=] j

AlekseyPX

1) Fundamental units of $\Psi$ are $[\frac{mol}{m\cdot s^2}]$

2) Fundamental units of $\Phi$ are $[\frac{mol}{m^3}]$

Explanation:

The equation for the variable $\rho$ is

$\rho =\frac{2\gamma \Phi+\Psi}{rg}$

where we have:

$\rho$ measured in $[\frac{mol}{ft^3}]$

$\gamma$ measured in $[\frac{J}{kg}]$

$r$ measured in $[in]$

$g$ measured in $[\frac{m}{s^2}]$

We can re-write the equation as

$\rho rg = 2\gamma \Phi + \Psi$

And we notice that the units of the term on the left must be equal to the units of the term on the right.

This means that:

1) First of all, $\Psi$ must have the same units of $\rho r g$ . So,

$[\rho r g]=[\frac{mol}{ft^3}][in][\frac{m}{s^2}]$

However, both ft (feet) and in (inches) are not fundamental dimensions: this means that they can be expressed as meters. Therefore, the fundamental units of $\Psi$ are

$[\Psi]=[\frac{mol}{m^3}][m][\frac{m}{s^2}]=[\frac{mol}{m\cdot s^2}]$