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Aleks04 [339]
2 years ago
9

A 100-meter sprint is a race using only the straight side of a racetrack. A 400-meter sprint is a race that makes one complete l

ap around a racetrack. Why are velocity and speed the same for 100-meters sprint but not a 400-m sprint?
Physics
2 answers:
Effectus [21]2 years ago
5 0
Velocity is a vector quantity and depends on both speed and direction.
In 100m you only travel straight in one direction.
But in 400m you have to turn corners and then go back the way you came, and then turn another corner, you're changing direction - hence changing velocity, even if the speed is the same.
DanielleElmas [232]2 years ago
3 0

In the 100-m sprint, the displacement is 100 meters and the distance is 100 meters. This means speed and velocity are the same for the 100-m sprint. In the 400-m sprint, the distance is 400-m, but the runners stop at the same place they start so the displacement is zero. Zero displacement means zero velocity.

yw!

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A badger is trying to cross the street. Its velocity vvv as a function of time ttt is given in the graph below where rightwards
Mrrafil [7]

Answer: -2.5

Explanation:

1/2(-5)= -2.5

-2.5(1)= -2.5

Got it right in Khan Academy. You’re welcome.

5 0
2 years ago
The image shows positions of the earth and the moon in which region would an astronaut feel the lightest
trapecia [35]

Answer:

The moon region

Explanation:

This is because there is little to no gravity on the moon. That is where the astronaut would feel the lightest.

5 0
1 year ago
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The difference in heights of the liquid in the two sides of the manometer is 43.4 cm when the atmospheric pressure is 755 mm hg.
Schach [20]

The atmospheric P is greater than the P in the flask, since the Hg level is lacking down lower on the side open to the atmosphere. 

43.4 cm x (10 mm / 1 cm) = 435 mm 

the density of Hg is 13.6 / 0.791 = 17.2 times better than the liquid in the manometer. This means that 1 mmHg = 17.2 mm of manometer liquid. 

435 mm manometer liquid x (1 mm Hg / 17.2 mm manometer liquid) = 25.3 mm Hg 

The pressure in the flask is 755 - 25.3 = 729.7 mmHg. 

729.7 mmHg x (1 atm / 760 mmHg ) = 0.960 atm.

4 0
2 years ago
 A bartender slides a beer mug at 1.50 m/s toward a customer at the end of a frictionless bar that is 1.20 m tall. The customer
Andrew [12]

Answer:

a) the mug hits the floor 0.7425m away from the end of the bar. b) |V|=5.08m/s θ= -72.82°

Explanation:

In order to solve this problem, we must first start by doing a drawing of the situation. (see attached picture).

a)

From the drawing we can see that we are dealing with a two dimensions movement problem. So in order to find out how far away from the bar the mug will fall, we need to start by finding how long it will take the mug to be in the air, so we analyze the vertical movement of the mug.

In order to find the time we need to use the following formula, which contains the data we know:

y_{f}=y_{0}+v_{y0}t+\frac{1}{2}at^{2}

we know that y_{f}=0 and that v_{y0}=0 as well, so the formula is simplified to:

0=y_{0}+\frac{1}{2}at^{2}

we can now solve this for t, so we get:

-y_{0}=\frac{1}{2}at^{2}

-2y_{0}=at^{2}

\frac{-2y_{0}}{a}=t^{2}

t=\sqrt{\frac{-2y_{0}}{a}}

we know that y_{0}=1.20m and that a=g=-9.8m/s^{2}

the acceleration of gravity is negative because the mug is moving downwards. So we substitute them into the given formula:

t=\sqrt{\frac{-2(1.20m)}{(-9.8m/s^{2})}}

which yields:

t=0.495s

we can now use this to find the horizontal distance the mug travels. We know that:

V_{x}=\frac{x}{t}

so we can solve this for x, so we get:

x=V_{x}t

and we can now substitute the values we know:

x=(1.5m/s)(0.495s)

which yields:

x=0.7425m

b) Now that we know the time it takes the mug to hit the floor, we can use it to find the final velocity in the y-direction by using the following formula:

a=\frac{v_{f}-v_{0}}{t}

we know the initial velocity in the vertical direction is zero, so we can simplify the formula:

a=\frac{v_{f}}{t}

so we can solve this for the final velocity:

V_{yf}=at

in this case the acceleration is the same as the acceleration of gravity (which is negative) so we can substitute that and the time we found on the previous part to get:

V_{yf}=(-9.8m/s^{2})(0.495s)

which yields:

V_{yf}=-4.851m/s

so now we know the components of the final velocity, which are:

V_{xf}=1.5m/s and V_{yf]=-4.851m/s

so now we can find the speed by determining the magnitude of the vector, like this:

|V|=\sqrt{V_{x}^{2}+V_{y}^{2}}

so we get:

|V|=\sqrt{(1.5m/s)^{2}+(-4.851m/s)^{2}

which yields:

|V|=5.08m/s

now, to find the direction of the impact, we can use the following equation:

\theta = tan^{-1} (\frac{V_{y}}{V_{x}})

so we get:

\theta = tan^{-1} (\frac{-4.851m/s}{(1.5m/s)})

which yields:

\theta = -72.82^{o}

4 0
2 years ago
A cord is wrapped around the rim of a solid uniform wheel 0.280m in radius and of mass 8.80kg. A steady horizontal pull of 32N t
Grace [21]

Answer:25.97 rad/s^2

Explanation:

Given

radius of wheel r=0.28 m

mass of wheel m=8.80 kg

Force F=32 N

Moment of Inertia of solid wheel I=\frac{mr^2}{2}

I=\frac{8.8\times 0.28^2}{2}

I=0.344 kg-m^2

Torque is given by

\tau =F\times r=I\times \alpha

32\times 0.28=0.344\times \alpha

\alpha =25.97 rad/s^2

Force on the axle is 32 N since there is no linear acceleration of the system

using Third law F=32 N

Torque of the axle applied to the wheel is zero because force of axle imparted at the center of axle

3 0
2 years ago
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