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3 years ago

A boy sledding down a hill accelerates at 1.40 m/s². If

Physics

1 answer:

mrs_skeptik [129]3 years ago

5 0

Answer: He would reach 7m/s at the distance of 17,5m.

Explanation: In order for us to know how long it takes for the speed to be reached, we use the equation V= Vo + at, with V=7m/s, Vo= 0m/s since you start from rest and a=1.4m/s². T is the time in seconds that we want to find out.

7 = 0 + 1.4t

7 = 1.4t

t= 5s

Now, we want to know the distance this boy reaches in 5 seconds, in a 7m/s speed and accelarating in 1.4m/s². For finding this out, we use another equation, S = So + Vot + (at²)/2, S being the final distance, So = 0m because he started from rest, and the other variables used before.

S = 0 + 0*5 + [1.4*(5²)]/2

S = 0 + 0 + (1.4*25)/2

S = 35/2

S = 17,5m

You might be interested in

A bicycle has a mass of 10kg and an acceleration of 2m/s². What is the net force of the bicycle?

kobusy [5.1K]

Answer:

<h3>The answer is 20 N</h3>

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

<h3>Force = mass × acceleration</h3>

From the question

mass = 10 kg

acceleration = 2 m/s²

We have

Force = 10 × 2

We have the final answer as

Hope this helps you

4 0

2 years ago

An electromagnetic wave is transporting energy in the negative y direction. At one point and one instant the magnetic field is i

natali 33 [55]

Answer:. Option c

Explanation: the speed of an electromagnetic wave is simply the vector product of the magnetic field and the electric field.

The direction of the velocity is the direction of the electromagnetic wave.

The wave is already moving towards the negative y axis (-j) and the magnetic field is already pointing towards the positive x axis (i)

From cross product of unit vectors

i × j = k

i × k = - j

With the second identity, we can see that the electric field will be pointing towards the positive of the x axis (k).

Option c is validated

4 0

2 years ago

Velocity of a car that travled 120 miles in 2 hours

Sophie [7]

60 Miles per hour 60 times 2 is 120

4 0

2 years ago

Read 2 more answers

The horse on a carousel is 3.5m from the central axis.A. If the carousel rotates at 0.13 rev/s , how long does it take the horse

Kitty [74]

Answer:

a. 15.4 seconds

b. 0.455 m/s

Explanation:

a. The carousel rotates at 0.13 rev/s.

This means that it takes the carousel 1 sec to make 0.13 of an entire revolution.

This means that time it will take to make a complete revolution is:

1 / 0.13 = 7.7 seconds

Therefore, the time it will take to make 2 revolutions is:

2 * 7.7 = 15.4 seconds

b. Let us calculate the linear velocity. Angular velocity is given as:

$\omega = v / r$

where v = linear velocity and r = radius

The radius of the circle is 3.5 m and the angular velocity is 0.13 rev/s, therefore:

0.13 = v / 3.5

v = 3.5 * 0.13 = 0.455 m/s

Linear velocity is 0.455 m/s

8 0

3 years ago

a solution made by dissolving 116 g of CaCl2 in 64 g of water has a density of 1.180 g/ml at 20 degrees celsius what is the mola

Makovka662 [10]

Answer:

The molarity of CaCl2 in the solution is 4.94 M

Explanation:

First of all you need to calculate CaCl2 mass.

You have one atom of Ca = 40.07 g/mol and two atoms of Cl = 35.45 g/mol so the molecule has a mass of 110.97 g/mol.

Now, knowing that your solution will have a mass of 64 grams of water + 116 grams of CaCl2 = 180 grams, you can calculate its volume, knowing that density = mass/volume

density x mass = volume --> 1,180 g/ml x 180 g = 212.4 ml

In 212.4 ml, you have 116 grams of CaCl2. You can calculate how many moles of CaCl2 you have:

110.97 g ------ 1 mol

116 g -------- x = (116 g x 1 mol) / 110.97 g = 1.05 moles

The molarity in a solution equals how many moles of a certain solute you have in 1000 ml of solution. In this solution, you have 1.05 moles in 212.4 ml, so in 1000 ml you will have:

212.4 ml ------- 1.05 moles

1000 ml -------- x = (1000 ml x 1.05 moles) / 212.4 ml = 4.94 moles.

This means the molarity of CaCl2 in the solution is 4.94 M.

4 0

3 years ago