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Mekhanik [1.2K]
4 years ago
14

A train travels 80 kilometers in 2 hours, and then 79 kilometers in 4 hours. What is its average speed?

Physics
1 answer:
Ludmilka [50]4 years ago
4 0
79 2/3 kilometers per hour
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Find the magnitude of the electric field at a point 0.35 m to the right of a sphere of a charge of 1.20×10^−6 C.
frozen [14]

https://mrsstowell.weebly.com/uploads/5/1/4/6/51460659/hsav_riverdale.k12.wi.us_20160330_092123.pdf

6 0
3 years ago
The electric potential inside a charged spherical conductor of radius R is is given by V = keQ/R, and the potential outside is g
Bumek [7]

Answer:

For outer points of shell

E = \frac{k_eQ}{r^2}

Now for inner point of shell

E = 0

Explanation:

As we know that out side the shell electric potential is given as

V = \frac{K_e Q}{r}

inside the shell the electric potential is given as

V = \frac{K_e Q}{R}

now we know the relation between electric potential and electric field as

E = - \frac{dV}{dr}

so we can say for outer points of the shell

E = -\frac{dV}{dr}

E = - \frac{d}{dr}(\frac{K_eQ}{r})

E = \frac{k_eQ}{r^2}

Now for inner point again we can use the same

E = - \frac{dV}{dr}

E = - \frac{d}{dr}(\frac{K_eQ}{R})

E = 0

6 0
3 years ago
. A bird is flying with a speed of 18.0 m/s over water when it accidentally drops a 2.00 kg fish. If the altitude of the bird is
zysi [14]
V^2 = u^2 + 2gr, where v - speed, u - initial speed=0, r - displacement (or height)
v^2 = 0 + 2*10*5.4
v = 10.2 m/s
4 0
3 years ago
Read 2 more answers
A 1.1 kg hammer strikes a nail. Before the impact, the hammer is moving at 4.5 m/s; after the impact it is moving at 1.5 m/s in
Talja [164]

Answer:

132 N

Explanation:

Given that a  1.1 kg hammer strikes a nail. Before the impact, the hammer is moving at 4.5 m/s; after the impact it is moving at 1.5 m/s in the opposite direction. If the hammer is in contact with the nail for 0.025 s, what is the magnitude of the average force exerted by the hammer on the nail

From Newton 2nd law of motion,

Change in momentum = impulse.

Change in momentum = m( V - U )

Substitute all the parameters into the formula

Change in momentum = 1.1 ( 4.5 - 1.5 )

Change in momentum = 1.1 × 3

Change in momentum = 3.3 kgm/s

Impulse = Ft

That is,

Ft = 3.3

Substitute time t into the formula above

F × 0.025 = 3.3

F = 3.3 / 0.025

F = 132 N

Therefore, the magnitude of the average force exerted by the hammer on the nail is 132 N.

3 0
4 years ago
A motion sensor acts as a transmitter when it sends out pulses and as a receiver when it listens for echoes. The delay ∆t betwee
Oksi-84 [34.3K]

Answer:

1.526 m

Explanation:

The motion sensor sends sound waves in air which travels at a speed of 343 m per second at 20 degree. If d be the distance of the reflecting object

total distance travelled = 2d

Time taken t = 8.9 x 10⁻³ s

velocity v  = 2d / t

343 = 2 d / (8.9 x 10⁻³)

d = 1.526 m

4 0
3 years ago
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