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natka813 [3]
3 years ago
10

Josie is running her first cross country meet. The race is a distance of 5 km and she has set a goal to finish the race in 21 mi

nutes. She must run at a speed of to meet this goal.
Physics
1 answer:
frutty [35]3 years ago
8 0

Answer:

3.97 m/s

Explanation:

Speed is defined as the distance covered per unit time. Therefore, s=d÷t=d/t

Where d is distance and t is time

Given distance of 5 km and time of 21 minutes the speed would be given by dividing 5 km by 21 min. However, speed is expressed as km/h or m/s or miles per hour etc. So we nees to get our speed in one of these standard units.

Going for m/s

Conversion

1 km has 1000m hence

5 km=5*1000=5000m

1 min has 60 seconds hence

21 min=21*60=1260 s

Speed=5000m÷1260s=3.9682539682538 m/s

Rounded off, s=3.97 m/s

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What property of matter determines how much inertia an object has
tester [92]
The mass of an object determines the object's inertia.
4 0
3 years ago
What is the slope of the line plotted below?<br> O A. -1<br> O B. 2<br> o<br> C. 2.<br> O D. 1
Tanya [424]

Answer:

-2

Explanation:

The points are (0, 3) and (3, -3)

If you subtract 3-(-3) you get 6

If you subtract 0-3 you get -3

6/-3 is equal to -2

7 0
3 years ago
When the current in a toroidal solenoid is changing at a rate of 0.0240 A/s , the magnitude of the induced emf is 12.4 mV . When
Gemiola [76]

Answer:

The number of turns in the solenoid is 230.

Explanation:

Given that,

Rate of change of current, \dfrac{dI}{dt}=0.0240\ A/s

Induced emf, \epsilon=12.4\ mV=12.4\times 10^{-3}\ V

Current, I = 1.5 A

Magnetic flux, \phi=0.00338\ Wb

The induced emf through the solenoid is given by :

\epsilon=L\dfrac{dI}{dt}

or

L=\dfrac{\epsilon}{(di/dt)}........(1)

The self inductance of the solenoid is given by :

L=\dfrac{N\phi}{I}.........(2)

From equation (1) and (2) we get :

\dfrac{\epsilon}{(di/dt)}=\dfrac{N\phi}{I}

N is the number of turns in the solenoid

N=\dfrac{\epsilon I}{\phi (dI/dt)}

N=\dfrac{12.4\times 10^{-3}\times 1.5}{0.00338 \times 0.024}

N = 229.28 turns

or

N = 230 turns

So, the number of turns in the solenoid is 230. Hence, this is the required solution.

3 0
3 years ago
5.) A 2000 N bear slides down a tree at a constant velocity, what is the
PilotLPTM [1.2K]

Answer:

2000 N

1600 N

Explanation:

Step 1:

It is given that the bear's weight is 2000 N and it slides down the tree with constant velocity. Since it is sliding with constant velocity the overall force  on the bear is zero. The weight of the bear acting downward balances the upward force caused due to friction. Hence the upward force equals the weight 2000 N.  

Step 2:

It is given that the bear slides down with an acceleration 2 m/sec sq  

Weight of the bear = 2000 N

Mass of the bear = 2000/10 (taking g = 10 m/sec sq)=200 kg

Force = Mass * Acceleration

Hence net force acting downward = 200*2=400 N.

Net force = Weight of bear - Force acting upward on the bear

400 = 2000 -  Force acting upward on the bear

Force on the bear acting upward = 2000 - 400 = 1600 N

4 0
3 years ago
A rock with a mass of 10.0kg falls 25.0m to
Jlenok [28]

Answer:

man brainly should put a rank for having negative points

Explanation:

that would be me right now

8 0
3 years ago
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