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3 years ago

You toss a marble straight up into the air with a speed of 1.3 m/s. How long does it take the marble to reach its highest point?

2 answers:

8 0

The acceleration of gravity is 9.8 m/s². That means that the speed of the marble is always 9.8 m/s greater downward than it was 1 second earlier.

You want to know when the marble is going to stop climbing. Well, that
will be when its upward velocity has dwindled to zero. That in turn is the
time when its upward velocity is 1.3 m/s less than it was when you tossed it.

(1.3 m/s) / (9.8 m/s²) = 0.133 second (rounded)

FromTheMoon [43]3 years ago

3 0

D
Reason:-
applying the formula
vf=vi+gt
1.3/9.8=t
0.13=t(Ans)

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What information can be determined by observing dark lines within the spectrum of a given star?

Scrat [10]

I believe the answer is D.

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3 years ago

A bowling ball with a momentum of 18kg-m/s strikes a stationary bowling pin. After the collision, the ball has a momentum of 13k

Veronika [31]

Answer:

$14.98\ \text{kg m/s}$

$45.26^{\circ}$

Explanation:

$P_1$ = Initial momentum of the pin = 13 kg m/s

$P_i$ = Initial momentum of the ball = 18 kg m/s

$P_2$ = Momentum of the ball after hit

$55^{\circ}$ = Angle ball makes with the horizontal after hitting the pin

$\theta$ = Angle the pin makes with the horizotal after getting hit by the ball

Momentum in the x direction

$P_i=P_1\cos55^{\circ}+P_2\cos\theta\\\Rightarrow P_2\cos\theta=P_i-P_1\cos55^{\circ}\\\Rightarrow P_2\cos\theta=18-13\cos55^{\circ}\\\Rightarrow P_2\cos\theta=10.54\ \text{kg m/s}$

Momentum in the y direction

$P_1\sin55=P_2\sin\theta\\\Rightarrow P_2\sin\theta=13\sin55^{\circ}\\\Rightarrow P_2\sin\theta=10.64\ \text{kg m/s}$

$(P_2\cos\theta)^2+(P_2\sin\theta)^2=P_2^2\\\Rightarrow P_2=\sqrt{10.54^2+10.64^2}\\\Rightarrow P_2=14.98\ \text{kg m/s}$

The pin's resultant velocity is $14.98\ \text{kg m/s}$

$P_2\sin\theta=10.64\\\Rightarrow \theta=sin^{-1}\dfrac{10.64}{14.98}\\\Rightarrow \theta=45.26^{\circ}$

The pin's resultant direction is $45.26^{\circ}$ below the horizontal or to the right.

4 0

3 years ago

Flying against the wind, an airplane travels 2670 km in 3 hours. Flying with the wind, the same plane travels 11,070 km in 9 hou

xxMikexx [17]

Answer:

speed of plane in still air = 1060 km/h

speed of wind = 170 km/h

Explanation:

Let teh speed of plane in still air is vp and the speed of air is va.

Irt travels 2670 km in 3 hours against the wind

So,

vp - va = 2670 / 3 = 890 km/h ..... (1)

It travels 11070 km in 9 hours along the wind.

vp + va = 11070 / 9 = 1230 km/h .... (2)

Adding both the equations

2 vp = 2120

vp = 1060 km/h

and va = 1230 - vp = 1230 - 1060 = 170 km/h

5 0

3 years ago

A truck travels to and from a stone quarry that is located 2.5km to the east.

Harrizon [31]

Answer:

Distance is 5.0 km and displacement is 0 km.

Explanation:

The diagram is shown below.

Distance is the total length that the truck covers along the complete journey. The truck moves from a stone quarry covering a length of 2.5 km and then again come back to the same point and thus covering another 2.5 km. Therefore, the total length covered by the truck is the sum of forward and backward paths which is equal to 5.0 km.

Now, displacement depends only on the initial and final position. It is given as the difference of final position and initial position. So, the truck starts from stone quarry and returns back to the same position. So, the initial position and final position is same. Therefore, the difference is 0 and hence displacement is zero.

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3 years ago

SOMEONE HELP PLEASE SORRY

evablogger [386]

Answer:

Just red light is reflected. Even if you shine a red laser at a blue piece of paper, only red light is reflected. ... The dot you see will probably always be red. If you do this in a bright room, you might trick yourself.

Explanation:

3 0

3 years ago