All categories

3 years ago

A skier starting from rest skis straight down a slope 50 meters long in 5.0 seconds. What is the magnitude of the acceleration.

1 answer:

6 0

His average speed all the way is

   (50 meters) / (5 sec) = 10 m/s .

But, if the acceleration is uniform all the way down, then

Average speed = (1/2) (start speed + end speed)

Start speed = 0.
So
   Average speed = (1/2) (0 + end speed)

   = (1/2) of end speed .

   10 m/s = (1/2) of end speed

   End speed (at the bottom) = 20 m/s .

Magnitude of acceleration = (change in speed) / (time for the change)

      = (20 m/s) / (5 sec)

   =    4 m/s² .

You might be interested in

Which of the following describes resistance?

enot [183]

D is your answer hope this helps

8 0

3 years ago

What are possible units for impulse? Check all that apply. kg • m kg • N • s N • m

Vlada [557]

We know that impulse is simply the product of Force and time:

Impulse = Force * time

Since Force has a unit of Newton or kg m/s^2 and time is in seconds, therefore impulse can have units as:

N s

kg m/s

4 0

3 years ago

A uniform disk, a thin hoop, and a uniform sphere, all with the same mass and same outer radius, are each free to rotate about a

olga nikolaevna [1]

Answer:

4 hoop, disk, sphere

Explanation:

Because

We are given data that

Hoop, disk, sphere have Same mass and radius

So let

And Initial angular velocity, = 0

The Force on each be F

And Time = t

Also let

Radius of each = r

So let's find the inertia shall we!!

I1 = m r² /2

= 0.5 mr² the his is for dis

I2 = m r² for hoop

And

Moment of inertia of sphere wiil be

I3 = (2/5) mr²

= 0.4 mr²

ωf = ωi + α t

= 0 + ( τ / I ) t

= ( F r / I ) t

So we can see that

ωf is inversely proportional to moment of inertia.

And so we take the

Order of I ( least to greatest ) :

I3 (sphere) , I1 (disk) , I2 (hoop) , ,

Order of ωf: ( least to greatest)

That of omega xf is the reverse of inertial so

hoop, disk, sphere

Option - 4

5 0

3 years ago

An object is placed perpendicular to the the principal axis of convex lens of focal length 8,the distance of the object from the

Digiron [165]

Answer:

v = 24 cm and inverted image

Explanation:

Given that,

The focal length of the object, f = +8 cm

Object distance, u = -12 cm

We need to find the position &nature of the image. Let v be the image distance. Using lens formula to find it :

$\dfrac{1}{v}-\dfrac{1}{u}=\dfrac{1}{f}$

Put all the values,

$\dfrac{1}{v}=\dfrac{1}{f}+\dfrac{1}{u}\\\\\dfrac{1}{v}=\dfrac{1}{8}+\dfrac{1}{(-12)}\\\\v=24\ cm$

So, the image distance from the lens is 24 cm.

Magnification,

$m=\dfrac{v}{u}\\\\m=\dfrac{24}{-12}\\\\m=-2$

The negative sign of magnification shows that the formed image is inverted.

7 0

2 years ago

This picture represents A: Reflection B: Refraction C: Interference D: Diffraction

-BARSIC- [3]

Answer:

I think it's a because it goes thru it and reflects

5 0

2 years ago