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3 years ago

What was the average speed in km/h of a car that travels 490.0 km in 4.2 h?

Physics

1 answer:

antoniya [11.8K]3 years ago

5 0

Answer:

<h2>Below</h2>

Explanation:

$Distance = 490 \:km\\Time = 4.2 \:hours\\\\Average\:speed = \frac{Distance}{Time} \\\\A.V = \frac{490}{4.2} \\\\A.V = 116.67km/h$

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What happens when a star exhausts its core hydrogen supply?

Allushta [10]

Answer:

It becomes a giant or supergiant.

Explanation:

Once all the hydrogen supply is gone, fusion of hydrogen into helium stops. The core starts to contract and liberates energy, which heats the superior layer until it becomes hot enough to start the fusion of hydrogen into helium.

6 0

3 years ago

The graph below represents the relationship between speed and time for an object moving along a straight line. What is the total

KiRa [710]

The distance travelled by the object during the first 4 seconds is 80 m

<h3>Definition of speed </h3>

Speed is defined as the distance travelled per unit time. Mathematically, it can be expressed as:

Speed = distance / time

With the above formula, we can obtain the distance travelled by the object in the first 4 seconds.

<h3>How to determine the distance travelled </h3>

Speed = 20 m/s
Time = 4 s

Distance =?

Speed = distance / time

20 = distance / 4

Cross multiply

Distance = 20 × 4

Distance = 80 m

Complete question:

See attached photo

Learn more about speed:

brainly.com/question/680492

4 0

2 years ago

An object experiences a net acceleration to the left. Which of the following statements about this object are true? There may be

dedylja [7]

Answer:

When an object experiences acceleration to the left, the net force acting on this object will also be to the left.
If the mass of the object was doubled, it would experience an acceleration of half the magnitude

Explanation:

When an object experiences acceleration to the left, the net force acting on this object will also be to the left.

From Newton's second law of motion, the acceleration of the object is given as;

a = ∑F / m

a = -F / m

The negative value of "a" indicates acceleration to the left

where;

∑F is the net force on the object

m is the mass of the object

At a constant force, F = ma ⇒ m₁a₁ = m₂a₂

If the mass of the object was doubled, m₂ = 2m₁

a₂ = (m₁a₁) / (m₂)

a₂ = (m₁a₁) / (2m₁)

a₂ = ¹/₂(a₁)

Therefore, the following can be deduced from the acceleration of this object;

When an object experiences acceleration to the left, the net force acting on this object will also be to the left.
If the mass of the object was doubled, it would experience an acceleration of half the magnitude

6 0

2 years ago

Bill and amy want to ride their bikes to school which is 14.4 kilometers away. It takes Amy 49 minutes to get to school and bill

Drupady [299]

3.4m/s

Explanation:

Given parameters:

Distance to school = 14.4km

Time taken by Amy = 49min

Time taken by bill = 20min after Amy = 20+49 = 69min

Unknown parameters:

How much faster is Amy's average speed = ?

Solution:

Average speed is the rate of change of total distance with total time taken.

Average speed = $\frac{total distance }{total time taken}$

convert units to meters and seconds

1000m = 1km

60s = 1min

Distance to school = 14.4 x 1000 = 14400m

Time taken by Amy = 49 x 60 = 2940s

Time taken by Bill = 69 x 60 = 4140s

Average speed of Amy = $\frac{14400}{2940}$ = 4.9m/s

Average speed of Bill = $\frac{4140}{2940}$ = 1.4m/s

Differences in speed = 4.9 - 1.5 = 3.4m/s

Amy was 3.4m/s faster than Bill

learn more:

Average speed brainly.com/question/8893949

#learnwithBrainly

5 0

3 years ago

the height of seven falls in colorado is 5/2 the height of twin falls in idahi. the sum of the two heights is 420 ft. find the h

Masja [62]

Let height of twin falls = x
height of seven falls = 2.5x

x + 2.5x = 420
3.5x = 420
x = 420/3.5 = 120

so twin falls = x = 120 ft
seven falls = 2.5x = 300 ft

6 0

2 years ago