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3 years ago

How do you work out instantaneous speed?

1 answer:

7 0

To calculate instantaneous speed, we need to divide part of the total distance traveled by time. However, we don't want to use the distance of the entire trip, because that will give us average speed.

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Beginning 145 miles directly south of the city of Hartville, a car travels due west. If the car is travelling at a speed of 42 m

ziro4ka [17]

Answer:

The rate of change of the distance is 14.89.

Explanation:

Given that,

Distance = 145 miles

Speed of car = 42 miles/hr

Distance covered by car = 55 miles

We need to calculate the the rate of change of the distance

According to figure,

Let OA is x, and AB is y.

Now, using Pythagorean theorem

$x^2=y^2+145^2$

On differentiating

$2x\dfrac{dx}{dt}=2y\dfrac{dy}{dt}$

$\dfrac{dx}{dt}=\dfrac{y}{x}\dfrac{dy}{dt}$

$\dfrac{dx}{dt}=\dfrac{55\times42}{\sqrt{55^2+145^2}}$

$\dfrac{dx}{dt}=14.89\ miles/hr$

Hence, The rate of change of the distance is 14.89.

8 0

3 years ago

A force of 20 N acts on a 4 kg cart for 10 s . How far will it go (using the second law) ?

Elden [556K]

This took me a short while to figure out, but I am still not entirely sure if this is correct, this is just from my basic understanding of Newtons Second Law of Motion.

You have a 4kg cart with a force of 20N acting on it.

The formula for working out the acceleration is.
a=Fnet÷mass

Substitute in the information.
a=20N÷4kg

Now you solve it to give you.
a=5m/s

So now what you should be able to do is figure out that after 10 seconds the cart travelling at 5m/s would have travelled 10 metres.

This is achieved by finding out how many 5's go into 10 which is 2.
So you do 5×2 which equals 10.

The 4kg cart has travelled 10 meters in 10 seconds with a force of 20N acting upon it.

I hope that this has helped you.

8 0

3 years ago

A particle moves on a line away from its initial position so that after t hours it is s = 6t2 + 2t miles from its initial positi

docker41 [41]

<span>32 mph
First, let's calculate the location of the particle at t=1, and t=4
t=1
s = 6*t^2 + 2*t
s = 6*1^2 + 2*1
s = 6 + 2
s = 8 t = 4
s = 6*t^2 + 2*t s = 6*4^2 + 2*4
s = 6*16 + 8
s = 96 + 8
s = 104
So the particle moved from 8 to 104 over the time period of 1 to 4 hours. And the average velocity is simply the distance moved over the time spent. So:
avg_vel = (104-8)/(4-1) = 96/3 = 32
And since the units were miles and hours, that means that the average speed of the particle over the interval [1,4] was 32 miles/hour, or 32 mph.</span>

6 0

3 years ago

Why are some electromagnetic waves harmful to you but others are not?

Tatiana [17]

Because for example a lightning bolt is an electromagnetic wave. Lighting bolts can hurt you or even kill you. But others waves cant harm you.
Hope this helps

8 0

4 years ago

Read 2 more answers

When we turn on a switch it helps complete the electric circuit and the current passes from the positive to the negative in the

Schach [20]

Answer:

We don't get shocked because of the type of materials used in the switch is a poor conductor of electricity

Explanation:

Yes it is quite amazing we don't get shocked, this is because of resistance of the type of materials used in the switch (non conductors of electricity) so that when you try to put on a switch no current passes through you, mostly the material are made from plastics Or ceramics which are actually poor conductors of electricity.

5 0

3 years ago