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4 years ago

A van moves with a constant speed of 100km/h. How far can it travel in 3 hours?

Physics

1 answer:

Molodets [167]4 years ago

6 0

For this problem the formula you need is below.

Rate Time = Distance

What you're asking is what the rate of the car was, so to do that, we must plug! (Rate will be represented by “x”)

First, we need to find out how many hours is 2 hours and 24 minutes. If there are 60 minutes in an hour, then we can just say 24 minutes is 24/60 or 2/5 hours. So 2 hours and 24 minutes equals 2.4 hours. Now we plug:

2.4x = 200

Then we divide both sides by 2.4:

2.4x/2.4 = 200/2.4

x = 83.33 kilometers per hour. is the answer

Hope this helps!

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Which statement about the accuracy and precision of measuring tools is

adelina 88 [10]

The true statement about the accuracy and precision of measuring tools is Tools cannot be both accurate and precise. The correct option is C.

<h3>What is accuracy?</h3>

When in an experiment, a value is measured 5 times, then if the values measured are same for most of the time or like three times out of five, it said to be accurate. The phenomenon is accuracy.

Precision is about comparing the values to each other then find them near to each other.

Accuracy compares the experimental value to the theoretical value.

So, when all the values are close to each other but not nearest to the theoretical value, then it is said to be precise but not accurate.

Thus, the correct option is C.

Learn more about accuracy.

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#SPJ1

4 0

2 years ago

A ball rolls off a desk at a speed of 2 m/s and lands 0.50 seconds later.

Hoochie [10]

Answer:

(a) The ball lands <u>1 m</u> ahead of the desk's base.

(b) The height of the desk is <u>1.225 m.</u>

Explanation:

Given:

Initial velocity of the ball is, $u_{0}=2\ m/s$

Time of flight of the ball is, $t=0.50\ s$

(a)

Let the ball fall at a distance of $x$ from the base of the desk and let the height of the desk be $y$ .

The given motion of the ball is a projectile motion that can be divided into 2 mutually perpendicular directions.

Now, considering only the horizontal motion of the ball. The ball not under the influence of any force in the horizontal direction.

Therefore, the distance covered by the ball horizontally is given as:

$x=v_0\times t\\x=2\times 0.50=1\ m$

So, the ball lands 1 m ahead of the desk's base.

(b)

Now, consider only the vertical motion of the ball. The ball is under the influence of gravity.

So, vertical distance can be obtained using Newton's equations of motion.

We use the following equation of motion:

$y-y_0=u_{oy}t+\frac{1}{2}gt^2$

Where,

$y_{0}\rightarrow \textrm{initial vertical position of ball}\\u_{oy}\rightarrow \textrm{initial vertical velocity}\\g\rightarrow \textrm{acceleration due to gravity}\\y\rightarrow \textrm{final position of ball vertically}$

Here, as the ball leaves the desk horizontally, initial velocity is only in the horizontal direction and doesn't have any component in the vertical direction. So, $u_{oy}=0\ m/s$

Plug in $y_0=h,y=0,g=-9.8,u_{oy}=0,t=0.5$ . Solve for $h$ .

$0-h=0+\frac{1}{2}(-9.8)(0.5)^2\\-h=-4.9\times 0.25\\h=1.225\ m$

Therefore, the height of the desk is 1.225 m.

6 0

3 years ago

why does a spark jump from your hand to the doorknob as you reach for the door after walking across a carpeted floor?

Anna11 [10]

<span>because electrical charge builds up otherwise know as static electricity</span>

8 0

3 years ago

Read 2 more answers

Calculate the change internal energy (Î´e) for a system that is giving off 45.0 kj of heat and is performing 855 j of work on th

adelina 88 [10]

The change in internal energy of a system is given by (second law of thermodynamics)
$\Delta U = Q + W$
where Q is the heat absorbed by the system and W is the work done on the system.

In order to correctly evaluate the internal energy change, we must be careful with the signs of Q and W:
Q positive -> Q absorbed by the system
Q negative -> Q released by the system
W positive -> W done on the system by the surroundings
W negative -> W done by the system on the surroundings

In our problem, the heat released by the system is $Q=-45 kJ=-45000 J$ (with negative sign since it is released by the system), and the work done is $W=-855 J$ still with negative sign because it is performed by the system on the surrounding, so the change in internal energy is
$\Delta U = Q +W=-45000 J - 855 J=-45855 J$

3 0

3 years ago

9. A weather satellite is launched from the ground and placed in orbit six times farther away from the earth's centre. The gravi

Vaselesa [24]

Answer: d

One thirty-sixth of

Explanation: Gravitational field or gravitational field strength obeys the inverse square law. The gravitational field is inversely proportional to the square of the earth distance. That is,

g = Gm/r^2

Where r = distance.

If weather satellite is placed in orbit six times farther away from the earth's centre, gravitational field will be one thirty-sixth of its initial value.

Therefore, the gravitational field experienced by the satellite in orbit is one thirty-sixth of the field that it experienced on the ground.

4 0

3 years ago