A train travelling at 18m/s accelerates uniformly at 2m/s² for 6 seconds. Calculate the final speed of the train.

a bike is moving with a velocity of 90km/hr.after applying break it stops in 5 sec. calculate the force applied by brakes .mass

pentagon [3]

Explanation:

initial velocity(u) = 90 km/s = 25 m/s

time (t) = 5 sec

mass (m) = 200 kg

final velocity (v) = 0 m/s

v = u + at

0 = 25 + a * 5

-25 = 5 a

-5 = a

Therefore acceleration = -5m/s²

Force = mass * acceleration

F = 200*-5

F = -1000 N

7 0

3 years ago

A human being can be electrocuted if a current as small as 55 mA passes near the heart. An electrician working with sweaty hands

evablogger [386]

Answer:

The lethal voltage for the electrician under those conditions is 126.5 V.

Explanation:

To discover what is the lethal voltage to the electrician we need to find out what is the voltage that produces 55 mA = 0.055 A when across a resistance of 2300 Ohms (Electrician's body resistancy). For that we'll use Ohm's Law wich is expressed by the following equation:

V = i*R

Where V is the voltage we want to find out, i is the current wich is lethal to the electrician and R is his body resistance. By applying the given values we have:

V = 0.055*2300 = 126.5 V.

The lethal voltage for the electrician under those conditions is 126.5 V.

4 0

3 years ago

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Falling raindrops frequently develop electric charges. Does this create noticeable forces between the droplets? Suppose two 1.8

umka2103 [35]

Answer:

a) $F=2.048\times 10^{-7}\ N$

b) $a=0.1138\ m.s^{-2}$

Explanation:

Given:

mass of raindrops, $m=1.8\times 10^{-6}\ kg$

charge on the raindrops, $q=+21\times 10^{-12}\ C$

horizontal distance between the raindrops, $r=0.0044\ m$

A)

From the Coulomb's Law the force between the charges is given as:

$F=\frac{1}{4\pi.\epsilon_0} .\frac{q_1.q_2}{r^2}$

we have:

$\epsilon_0=8.854\times 10^{-12}\ C^2.N^{-1}.m^{-2}$

Now force:

$F=\frac{1}{4\pi\times 8.854\times 10^{-12}} .\frac{21\times 10^{-12}\times 21\times 10^{-12}}{0.0044^2}$

$F=2.048\times 10^{-7}\ N$

B)

Now the acceleration on the raindrops due to the electrostatic force:

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

$a=\frac{2.048\times 10^{-7}}{1.8\times 10^{-6}}$

$a=0.1138\ m.s^{-2}$

7 0

3 years ago

Read 2 more answers

A molecule that moves across a cell membrane without using the cell’s energy tends to move

zaharov [31]

Answer:answer is b

Explanation:

4 0

3 years ago

Which amusement park ride utilizes periodic motion?

hjlf

Periodic motion implies that the ride oscillates back and forth. The period is the time it takes to complete one cycle. Therefore it would be the swing.

6 0

3 years ago