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RUDIKE [14]
3 years ago
10

You drive on Interstate 10 from San Antonio to Houston, half the time at 72 km/h and the other half at 98 km/h. On the way back

you travel half the distance at 72 km/h and the other half at 98 km/h. What is your average speed (a) from San Antonio to Houston, (b) from Houston back to San Antonio, and (c) for the entire trip?
Physics
1 answer:
zimovet [89]3 years ago
7 0

Answer: a. 85km/hr b.82.3km/hr

c. 84km/hr

Explanation: first let take the total time from San Antonio to Houston to be 2hr.

Half time 1hr was covered with speed of 72km/hr

Distance = speed*time=72km/hr *1hr

=72km

So too with the second half of 1hr covered with speed of 98km/hr

Distance = 98km

Total distance from Houston to San Antonio is 98+72 =170km

a. Average speed from San Antonio to Houston is

S1 =170/2

=85km/hr

b.half distance from Houston to San Antonio which is 170km/2

= 85km was covered with speed of 72km/hr first half, so time

t = dist/speed

t = 85/72 = 1hr 12 mins

Remaining 85 km covered with a speed of 98km/hr

Time = 85/98 = 0.88*60min

= 52 mins

Total time = 1hr +12mins +52mins

=2hr4mins= 124/60 hr

So average speed = distance/time

=170/124/60

Using reciprocal law

Average speed S2= 170*60/124

= 82.3km/hr

C. Average speed to and fro(entire tripe)

= (85+82.3)/2

=84km/hr

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George is applying a downward force of 50N to and object that has a mass of 50kg. What is the normal force (FN) of the object wh
attashe74 [19]

The normal force acting on the object is 500 N in the upward direction

<u>Explanation:</u>

As George is applying a downward force, the normal force will be in the upward direction. The normal force will be exerted due to the acceleration due to gravity exerted on the object.

So, as per Newton's second law, the normal force acting on the object can be measured by the product of mass of the object and the acceleration due to gravity acting on the object.

But as the acceleration due to gravity is a downward acting acceleration and the normal force is a upward acting force, so the acceleration will be having a negative sign in the formula.

Normal\ force = Mass \times Acceleration\ due\ to\ gravity

Here, acceleration due to gravity g = -10 m/s² and mass is given as 50 kg, then

Normal force = 50 × (-10) = -500 N

So, the normal force acting on the object is 500 N in the upward direction.

3 0
3 years ago
If two children, with masses of 16 kg and 25 kg, sit in seats opposite one another in a rotating merry-go-round with an arm leng
Jlenok [28]

Answer:

92.25 kgm^2

Explanation:

Assume both children bodies are point particles. The total moment of inertia about the rotation axis of 2 points particles of mass 16 kg and 25 kg at 1.5 m arm length is

\sum I = m_1r_1^2 + m_2r_2^2

where m_1 = 16 kg, m_2 = 25 kg are the masses of 2 children r_1 = R-2 = 1.5m are their distance to the center of rotation

\sum I = 16*1.5^2 + 25*1.5^2 = 1.5^2(16 + 25) = 92.25 kgm^2

4 0
3 years ago
A marble column of cross-sectional area 1.6 m^2 supports a mass of 26600 kg. The elastic modulus for marble is 5.0 times 10^10 N
vodka [1.7K]

Answer:

Δ L = 2.57 x 10⁻⁵ m

Explanation:

given,

cross sectional area = 1.6 m²

Mass of column = 26600 Kg

Elastic modulus, E = 5 x 10¹⁰ N/m²

height = 7.9 m

Weight of the column = 26600 x 9.8

                                    = 260680 N

we know,

Young's modulus=\dfrac{stress}{strain}

stress = \dfrac{P}{A}

           = \dfrac{260680}{1.6}

           = 162925

strain = \dfrac{\Delta L}{L}

now,

Y = \dfrac{stress}{strain}

\Delta L = \dfrac{162925}{Y}\times L

\Delta L = \dfrac{162925}{5 \times 10^10}\times 7.9

   Δ L = 2.57 x 10⁻⁵ m

The column is shortened by Δ L = 2.57 x 10⁻⁵ m

3 0
3 years ago
What TWO things affect the gravitational force acting on an object?
ohaa [14]
The strength of the gravitational forces between two masses depends on

--  the product of the masses,

-- the distance between their centers of mass.
3 0
3 years ago
Read 2 more answers
The GPE of a 70kg person standing on a chair 1m off the ground is how many joules?
Artemon [7]
GPE I am assuming is gravitational potential energy. I'll denote it as U for simplicity. 

U = mgy
U = (70kg)(9.81m/s^2)(1m) = 686.7J

U = 686.7J

Hope this helps!
8 0
3 years ago
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