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3 years ago

7

11. You are in the frozen food section of the grocery store and you notice that your hand gets cold when you place it on the gla

ss windows of the display cases. Your friend says this is because coolness is transferred from the display case to your hand. What do you think?

1 answer:

Flauer [41]3 years ago

3 0

Explanation:

it happens in the morning time

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Someone help please by providing work and answers please :)

Nastasia [14]

First we gotta use an equation of motion:

$d = ut + \frac{1}{2} a {t}^{2}$

Our vertical distance d= 100 m, initial vertical speed u = 0 m/s (because velocity is fully horizontal), and vertical acceleration a = 9.8 m/s2 because of gravity. Let's plug it all in!

$100 = 0 + \frac{1}{2} (9.8) {t}^{2}$

Now we just need to solve for t:

${t}^{2} = \frac{2(100)}{9.8} \\ \\ t = \sqrt{\frac{2(100)}{9.8}}$

Hit the calculators, and you'll get 4.5 seconds!

5 0

2 years ago

How does changing the potential difference in a circuit affect the current and the resistance?

Effectus [21]

Answer:

The current will be increased and also for the resistance.

Explanation:

The analysis of a direct current circuit can give us the explanation we need. Using the ohm law, which tells us that the voltage is equal to the product of the current by the resistance we have:

$V=I*R\\where\\V= voltage [V]\\I= amperes [amp]\\R=resistance [ohm]\\$

The voltage is equal to the potential difference therefore we will have these expressions:

$I=\frac{V}{R} \\R= \frac{V}{I}$

If we increase the potential differential or circuit voltage, the current will also increase and so does the resistance by increasing the voltage. If we put numerical values in the equation given before, we can confirm this fact.

4 0

2 years ago

He power output of a cyclist moving at a constant speed of 5.3 m/s on a level road is 120 w. (a) what is the force exerted on th

EleoNora [17]

P=F*V
F=P/V
F=120/5.3
F=22.6N

8 0

3 years ago

Two soccer players kick a soccer ball back and forth along a straight line. The first player kicks the ball 16 m to the right to

Oliga [24]

Answer:

a

The total distance is $d_t =19.1 m$

b

The displacement is

$D_t = 12.9m$

Explanation:

From the question we are told that

Distance traveled by the ball for first player $d_f = 16m$ to the right

Distance traveled by the ball for second player $d_s = 3.1 m$ to the left

The total distance traveled by the ball is mathematically represented as

$d_t = d_f + d_s$

Substituting values

$d_t = 16 + 3.1$

$d_t =19.1 m$

The displacement is mathematically represented as

$D_t = d_f -d_s$

This is because displacement deal with direction and from the question we are told that right is positive and left is negative

Substituting values

$D_t = 16 -3.1$

$D_t = 12.9m$

5 0

3 years ago

Part A If the velocity of a pitched ball has a magnitude of 47.5 m/s and the batted ball's velocity is 51.5 m/s in the opposite

nalin [4]

Explanation:

Let us assume that the mass of a pitched ball is 0.145 kg.

Initial velocity of the pitched ball, u = 47.5 m/s

Final speed of the ball, v = -51.5 m/s (in opposite direction)

We need to find the magnitude of the change in momentum of the ball and the impulse applied to it by the bat. The change in momentum of the ball is given by :

$\Delta p=m(v-u)\\\\\Delta p=0.145\times ((-51.5)-47.5)\\\\\Delta p=-14.355\ kg-m/s$

So, the magnitude of the change in momentum of the ball is 14.355 kg-m/s.

Let the the ball remains in contact with the bat for 2.00 ms. The impulse is given by :

$J=\dfrac{\Delta p}{t}\\\\J=\dfrac{14.355}{2\times 10^{-3}}\\\\J=7177.5\ kg-m/s$

Hence, this is the required solution.

7 0

3 years ago