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3 years ago

A race car circles 10 times around a circular 8.0-km track in 20 min.

2 answers:

6 0

Find the average speed and the average velocity.

Average speed = distance / time

distance = 10 x 8000 m = 80,000 m
time = 20 min * 60 s/min = 1200 s

Average speed = 80,000 m / 1200 s = 66.67 m/s

Average velocity = displacement / time

Given that the race car made complete circles the final poin is the same initial point, then its displacement is zero and the average velocity is zero too.

fredd [130]3 years ago

5 0

Assuming that you're asking for the average speed,

Average speed = distance / time

since he circle 8 km track 10 times, the distance is 80,000 m and the time is 20 min or 1200 seconds
Average speed = 80,000 / 1200 = 66.67 m/s

Hope this helps

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An object in free fall travels a distance s that is directly proportional to the square of the time t. If an object falls 1088 f

ikadub [295]

Answer:

1,700feet

Explanation:

If an object in free fall travels a distance s that is directly proportional to the square of the time t, this can be represented mathematically as;

S = kt²where;

k is the proportionality constant

K = s/t²

s1/t1²= s2/t2²= Sn/tn²= k for values of the distance and time. Using the formula

s1/t1² = s2/t2² where;

s1 is the falling distance in time t1 s2 is the falling distance in time t2

Given s1 = 1088feet, t1 = 8secs, s2 = ? t2 = 10secs

Substituting this value in the formula to get s2, we have;

1088/8²= s2/10²

64s2= 108800

s2 = 108800/64

s2 = 1,700feet

This means the object will fall a distance of 1,700feet in 10seconds

5 0

3 years ago

If you are driving 120 km/h along a straight road and you look to the side for 2.0 s , how far do you travel during this inatten

Delicious77 [7]

120 km / 60 min

2 km / 1 min

1 km / 30 sec

0.5 km / 15 sec

0.03333 km / sec

0.03333 km = 33.33 m

8 0

3 years ago

Gravity causes objects to be attracted to one another. This attraction keeps our feet firmly planted on the ground and causes th

Airida [17]

F = G m1*m2 / r^2 => [G] = [F]*[r]^2 /([m1]*[m2]) = N * m^2 / kg^2

That is one answer.

Also, you can use the fact that N = kg*m/s^2

[G] = kg * m / s^2 * m^2 / kg^2 = m^3 /(s^2 * kg)

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3 years ago

What is the rate of 12 liters of water moving through a water hose in 4.0 minutes?

Basile [38]

3 liters per minute

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3 years ago

A 25 pF parallel-plate capacitor with an air gap between the plates is connected to a 100 V battery. A Teflon slab (dielectric c

adoni [48]

Answer:

The change in the charge on the positve plate when the Teflon is inserted is +2.5 nC.

Explanation:

It can be showed that the capacitance of a parallel-plate capacitor, can be expresssed as follows:

$C = \frac{\epsilon*A}{d}$

Where ε, is the dielectric constant of the material that fills the space between plates.
When this space is filled with air, ε= ε₀ = 8,85*10⁻¹² F/m.
At the same time, the capacitance of a capacitor, by definition, is as follows:

$C =\frac{Q}{V}$

If we insert a Teflon slab, in such a way that fills completely the gap between the plates, all other parameters being equal, if ε = 2*ε₀, this means that C₂ = 2* C₁. = 50 pF
As V₂=V₁ (due to the capacitor remains connected to the same battery) the charge must be the double, so Q₂ = 2* Q₁ = 5 nC.
So, the change in the charge of the positive plate is +2.5 nC.

3 0

3 years ago