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2 years ago

As your skateboard coasts uphill, your speed changes from 3 m/s to 1 m/s in

Physics

1 answer:

vlada-n [284]2 years ago

7 0

Answer:

$a=-0.33\ m/s^2$

Explanation:

<u>Accelerated Motion</u>

The acceleration of a moving body is defined as the relation of change of speed (or velocity in vector form) with the time taken. The formula is given by

$\displaystyle a=\frac{\Delta v}{t}$

Or, equivalently

$\displaystyle a=\frac{v_f-v_o}{t}$

Where vf and vo are the final and initial speeds respectively. The problem gives us these values: v0 = 3 m/s, vf = 1 m/s, t = 3 seconds. Computing a

$\displaystyle a=\frac{1-3}{3}=-0.33\ m/s^2$

The negative sing of a indicates there is deceleration or decreasing speed

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A driver drives for 30.0 minutes at 80.0 km/h, then 45.0 minutes at 100 km/h. She then stops 30 minutes for lunch. She then trav

bija089 [108]

Answer:

b) 68,9 km/h a) picture

Explanation:

In this problem, since velocity is expressed in km/h and time in minutes, we have to convert either time to hours or velocity to km/min. It is easier to use hours.

Using this formula we pass time to hours:

$t_{hours}=t_{min}*\frac{1 h}{60 min}\\30min*\frac{1 h}{60 min}=0,5h\\45min*\frac{1 h}{60 min}=0,75h$

Now we can plot speed vs time (image 1). The problem says that the driver uses constant speed, so all lines have to be horizontal.

Using the values of the speed we calculate the distance in each interval

$d=v*t\\80km/h*0.5h=40km\\100km/h*0.75h=75km$

Using these values and the fact that she was having lunch in the third one (therefore stayed in the same position), we plot position vs time, using initial position zero (image 2, distance is in km, not meters).

Finally, we compute the average speed with the distance over time:

$v_{average}=\frac{155km}{2.25h}=68.9km/h$

6 0

2 years ago

Imagine how mercury might be different if it had the same mass as earth. Explain.

maxonik [38]

I believe if it were heavier with more mass, then the sun would pull it in and there would be no mercury. It might also be hotter.

4 0

2 years ago

Two charged objects have a repulsive force of 0.040 N. If the distance separating the objects is doubled, then what is the new f

Georgia [21]

Answer:

Two charged objects have a repulsive force of 0.080 N. If the charge of both of the objects is doubled, then what is the new force? Explanation: Electrostatic force is directly related to the charge of each object. So if the charge of both objects is doubled, then the force will become four times greater.

Explanation:

hope this helps

7 0

2 years ago

Can a physical quantity have different dimensions in different systems of units?

Mars2501 [29]

Answer: yes a quantity have different dimensions in different system of units . No,because in different system of units doesn't change the quantity but it only changes the numerical.

Good luck !

4 0

2 years ago

Read 2 more answers

In a real system of levers, wheels, or pulleys, the AMA is less than the IMA because _____.

pickupchik [31]

In a real system of levers, wheels, or pulleys, the AMA is less than the IMA because of friction.
AMA (Actual mechanical advantage) is found by dividing output force by effort force. The actual mechanical advantage will always be less than the ideal mechanical advantage. The ideal mechanical advantage assumes perfect efficiency which doesn't account for friction, while actual mechanical advantage does. Therefore; the IMA is always greater than the actual mechanical advantage because all machines must overcome friction.

5 0

2 years ago