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A 2 kg stone moves with a speed of 1 m/s. A second 2 kg stone is moving twice as fast. Compare their kinetic energies.

alekssr [168]

D
is the answer
Well it should be

5 0

2 years ago

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Calculate the average velocity in m/y of a tectonic plate that has travelled 9000 km to the south in 60 million years

Gekata [30.6K]

The distance covered by the tectonic plate, in meters, is
 $d=9000km=9\cdot 10^6 m$ 
The time taken for the tectonic plate to cover this distance is equal to
 $t=60 mil.y=60 \cdot 10^6 y$ 
Therefore, the average velocity of the tectonic plate is the ratio between the distance covered and the time taken:
 $v= \frac{S}{t} = \frac{9\cdot 10^6m}{60 \cdot 10^6y} =0.15 m/y.$

8 0

2 years ago

Block A, mass 250 g , sits on top of block B, mass 2.0 kg . The coefficients of static and kinetic friction between blocks A and

masha68 [24]

Answer:

F = 69.3 N

Explanation:

For this exercise we use Newton's second law, remembering that the static friction force increases up to a maximum value given by

fr = μ N

We define a reference system parallel to the floor

block B ( lower)

Y axis

N - W₁-W₂ = 0

N = W₂ + W₂

N = (M + m) g

X axis

F -fr = M a

for block A (upper)

X axis

fr = m a (2)

so that the blocks do not slide, the acceleration in both must be the same.

Let's solve the system by adding the two equations

F = (M + m) a (3)

a = $\frac{F}{ M+m}$

the friction force has the formula

fr = μ N

fr = μ (M + m) g

let's calculate

fr = 0.34 (2.0 + 0.250) 9.8

fr = 7.7 N

we substitute in equation 2

fr = m a

a = fr / m

a = 7.7 / 0.250

a = 30.8 m / s²

we substitute in equation 3

F = (2.0 + 0.250) 30.8

F = 69.3 N

5 0

2 years ago

Draw the vector C⃗ =1.5A⃗ −3B⃗ . The length and orientation of the vector will be graded. The location of the vector is not impo

Nutka1998 [239]

I made the drawing in the attached file.

I included two figures.

The upper figure shows the effect of:

- multiplying vector A times 1.5.
It is drawn in red with dotted line.

- multiplying vector B times - 3 .
It is drawn in purple with dotted line.

In the lower figure you have the resultant vector: C = 1.5A - 3B.

The method is that you translate the tail of the vector -3B unitl the point of the vector 1,5A, preserving the angles.

Then you draw the arrow that joins the tail of 1,5A with the point of -3B after translation.

The resultant arrow is the vector C and it is drawn in black dotted line.

Download pdf

7 0

2 years ago

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A 1000-kg car is slowly picking up speed as it goes around a horizontal curve whose radius is 100 m. The coefficient of static f

Snezhnost [94]

Answer:

18.5 m/s

Explanation:

On a horizontal curve, the frictional force provides the centripetal force that keeps the car in circular motion:

$\mu mg = m\frac{v^2}{r}$