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3 years ago

17. In which layer does mantle convection occur?

Physics

1 answer:

Anarel [89]3 years ago

8 0

Answer:

D. Asthenosphere

Explanation:

The asthenosphere is relatively plastic part of the mantle which underlies the brittle lithosphere. In the asthenosphere, it is generally believed that the rocks are in ductile state and easily moves. It is the site of convection within the earth. In mantle convection, hot and light materials rises and keeps moving into upper crustal levels till they solidify. Here also, cold and denser materials sinks deeper till they turn to melt. This differences in temperature and density sets up a convective cell within the mantle. Several convective cells are in the mantle.

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1. A pendulum has a period of 3 seconds. What's its frequency? 2. A pendulum has a frequency of 0.25 Hz. What's its period? 3. A

RideAnS [48]

Answer:

(1) 0.333 Hz

(2) 4 sec

(3) 2 sec, 0.5 Hz

Explanation:

(1) We have given time period of pendulum is 3 sec

So T = 3 sec

Frequency will be equal to $f=\frac{1}{T}=\frac{1}{3}=0.333Hz$

(2) Frequency of the pendulum is given f = 0.25 Hz

Time period is equal to $T=\frac{1}{f}=\frac{1}{0.25}=4sec$

(3) It is given that a pendulum makes 10 back and forth swings in 20 seconds

So time taken to complete 1 back and forth swings = $=\frac{20}{10}=2sec$

So time period T = 2 sec

Frequency will be equal to $f=\frac{1}{T}=\frac{1}{2}=0.5Hz$

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2 years ago

Read 2 more answers

A racquetball strikes a wall with a speed of 30 m/s and rebounds in the opposite direction with a speed of 26 m/s. The collision

Fudgin [204]

Answer:

The average acceleration of the ball during the collision with the wall is $a=2,800m/s^{2}$

Explanation:

Known Data

We will asume initial speed has a negative direction, $v_{i}=-30m/s$ , final speed has a positive direction, $v_{f}=26m/s$ , $\Delta t=20ms=0.020s$ and mass $m_{b}$ .

Initial momentum

$p_{i}=mv_{i}=(-30m/s)(m_{b})=-30m_{b}\ m/s$

final momentum

$p_{f}=mv_{f}=(26m/s)(m_{b})=26m_{b}\ m/s$

Impulse

$I=\Delta p=p_{f}-p_{i}=26m_{b}\ m/s-(-30m_{b}\ m/s)=56m_{b}\ m/s$

Average Force

$F=\frac{\Delta p}{\Delta t} =\frac{56m_{b}\ m/s}{0.020s} =2800m_{b} \ m/s^{2}$

Average acceleration

$F=ma$ , so $a=\frac{F}{m_{b}}$ .

Therefore, $a=\frac{2800m_{b} \ m/s^{2}}{m_{b}} =2800m/s^{2}$

8 0

2 years ago

A typical running track is an oval with 74-mm-diameter half circles at each end. A runner going once around the track covers a d

lisabon 2012 [21]

The centripetal acceleration a is 4.32 $\times$ 10^-4 m/s^2.

Explanation:

The speed is constant and computing the speed from the distance and time for one full lap.

Given, distance = 400 mm = 0.4 m, Time = 100 s.

Computing the v = 0.4 m / 100 s

v = 4 $\times$ 10^-3 m/s.

radius of the circular end r = 37 mm = 0.037 m.

centripetal acceleration a = v^2 / r

= (4 $\times$ 10^-3)^2 / 0.037

a = 4.32 $\times$ 10^-4 m/s^2.

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2 years ago

Why is it important to know the direction of the force applied to a moving object and the direction in which the object is movin

ELEN [110]

C is correct. The work-force relation is given by W=F·d, where F is force vector, and d is the displacement vector. The dot is the dot product, which is a measure of how parallel the two vectors are. It can be restated as the product of two vector magnitudes times the cosine of the angle between them. Therefore work is a scalar, not a vector, since the dot product returns a scalar.
$W=Fdcos(\theta)$

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3 years ago

A student uses 150 N to push a block of wood up a ramp at constant velocity of 2.6m/s. What is his power output?

11Alexandr11 [23.1K]

Answer:

P= 390 W

Explanation:

In physics, power is the rate of doing work or of transferring heat, i.e. the amount of energy transferred or converted per unit time. Work is a force F applied over a distance x. Matemathicaly it means

P = dW/dt ≈ d(F * x)/dt = xdF/dt + Fdx/dt. If force is constant dF/dt=0 so P=F dx/dt = P*v, where v is velocity, the rate of distance per unit time.

We have force and velocity. Newton is unit of Kg*m/s2, hence

P= 150 kgm/s2 * 2.6 m/s =390 Kgm2/s3 = 390 W, where W is Watts and is an unit of power

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3 years ago