Who are the scientists given credit for discovering electrons, protons, and neutrons?

A child pushes horizontally on a box of mass m which moves with constant speed v across a horizontal floor. The coefficient of f

dexar [7]

Answer:

Explanation:

Given

mass of box is m

speed of box is v

coefficient of friction $\mu =\frac{1}{4}=0.25$

Box is moving at a constant speed i.e. Net Force on box is zero

i.e. Frictional Force and Force Applied are Equal

$F=f_r=\mu mg$

The Rate at which power is generated is

$P=F\cdot v$

$P=\mu mg\cdot v$

$P=0.25mgv$

4 0

3 years ago

horizontal force pushes block up a 20.0 incline with an initial speed 12.0 m//s. a) how high up the plane does slide before comi

Annette [7]

Answer:

Explanation:

We shall apply conservation of mechanical energy .

initial kinetic energy = 1/2 m v²

= .5 x m x 12 x 12

= 72 m

This energy will be spent to store potential energy . if h be the height attained

potential energy = mgh , h is vertical height attined by block

= mg l sin20 where l is length up the inclined plane

for conservation of mechanical energy

initial kinetic energy = potential energy

72 m = mg l sin20

l = 72 / g sin20

= 21.5 m

deceleration on inclined plane = g sin20

= 3.35 m /s²

v = u - at

t = v - u / a

= (12 - 0) / 3.35

= 3.58 s

it will take the same time to come back . total time taken to reach original point = 2 x 3.58

= 7.16 s

7 0

3 years ago

Question 10 of 34

labwork [276]

Julia walks from the park, which is six blocks east of her house, to the store, which is three blocks east of her house. Julia walks for 5 minutes. This walk's average speed will be 1.2 blocks per minute. Option B is correct.

<h3>What is displacement?</h3>

Displacement is defined as the shortest distance between the two points. Distance is the horizontal length covered by the body. While displacement is the shortest distance between the two points.

Displacement is a vector quantity .its unit is m.

The average velocity on this walk will be;

$\rm v_{avg}= \frac{d}{t} \\\\ \rm v_{avg}= \frac{6 \ block+ 3 \ block }{5 \ minute } \\\\ v_{avg}=1.4 \ block /min$

Hence option B is correct.

To learn more about displacement refer to the link; brainly.com/question/10919017

#SPJ1

3 0

2 years ago

Charlie runs at an average speed of 6.5 km/hr. If he runs for 1.5 hours, how far has he traveled?

VikaD [51]

Answer:

9.75 km

Explanation:

Charlie runs 6.5 km/hr

-> Charlie wants to run for 1.5 hours

6.5km + 6.5km/2

= 6.5 km + 3.25km

= 9.75 km

8 0

3 years ago

Choose the scenario under which each of the given Doppler shift effects will be seen.a. The source and observer are approaching

kkurt [141]

Answer:

scenario A and B

Explanation:

The Doppler effect is the change in frequency of a wave by the relative movement of the source and the observer. It is described by the expression

f ’= (v + v₀) / (v - $v_{s}$ ) f₀

Where f₀ is the emitted frequency, v the speed of the wave, v₀ and $v_{s}$ the speed of the observer and the source, respectively, the signs are for when they are approaching and in the case of being away the signs are changed.

Consequently, from the above for the Doppler effect to exist there must be a relative movement of the source and the observer.

Let's examine the scenarios

A) True. You agree with the equation shown

B) True. Only the signs should be changed and it is described by the equation shown

C) False. If there is no relative movement there is no Doppler effect

8 0

3 years ago