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3 years ago

The position of a particle is given by ~r(t) = (3.0 t2 ˆi + 5.0 ˆj j 6.0 t kˆ) m

Physics

1 answer:

Julli [10]3 years ago

5 0

Answer:

$v=(6ti+6k)\ m/s$

Explanation:

Given that,

The position of a particle is given by :

$r(t) = (3.0 t^2 i + 5.0j+ 6.0 tk) m$

Let us assume we need to find its velocity.

We know that,

$v=\dfrac{dr}{dt}\\\\=\dfrac{d}{dt}(3.0 t^2 i + 5.0j+ 6.0 tk) \\\\=(6ti+6k)\ m/s$

So, the velocity of the particle is $(6ti+6k)\ m/s$ .

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A pulsar is a rapidly rotating neutron star. The Crab nebula pulsar in the constellation Taurus has a period of 33.5\times 10^{-

joja [24]

Answer:

$5.25\cdot 10^{40} kg m^2/s$

Explanation:

The angular momentum of the pulsar is given by:

$L=m\omega r^2$

where

$m=2.8\cdot 10^{30} kg$ is the mass of the pulsar

$r = 10.0 km = 1\cdot 10^4 m$ is the radius

$\omega$ is the angular speed

Given the period of the pulsar, $T=33.5\cdot 10^{-3} s$ , the angular speed is given by

$\omega=\frac{2\pi}{T}=\frac{2 \pi}{33.5\cdot 10^{-3}s}=187.5 rad/s$

And so, the angular momentum is

$L=m\omega r^2=(2.8\cdot 10^{30}kg)(187.5 rad/s)(1\cdot 10^4 m)^2=5.25\cdot 10^{40} kg m^2/s$

8 0

3 years ago

A wheel is being turned to open a valve on a compressor. The resistance that is applied to the axle of the valve is 235 lb. The

SIZIF [17.4K]

Answer:

3.8 in

Explanation:

A wheel and axle machine is a machine in which the wheel rotates around the rod (axle). They rotate together thereby transferring force among each other.

The formula for a wheel and axle is:

Fr * Rr = Fe * Re

Where Fr is the resistance force, Rr is the radius of the resistance force, Fe is the effort force and Re is the radius of the resistance force.

Given that: Fr = 235 lb, Fe = 45 lb, Re = 20 in / 2 = 10 in. Hence:

235 * Rr = 45 * 10

Rr = 45 * 10 / 235

Rr= 1.9 in

Diameter of axle = 2 * 1.9 = 3.8 in

3 0

3 years ago

A block of mass 500g is pulled from rest on ahorizontal frictionless bench by a steady force F and travels 8m in 2s find the acc

Korvikt [17]

We are Given:

Mass of the block (m) = 500 grams or 0.5 Kg

Initial velocity of the block (u) = 0 m/s

Distance travelled by the block (s) = 8 m

Time taken to cover 8 m (t)= 2 seconds

Acceleration of the block (a) = a m/s²

Solving for the acceleration:

From the seconds equation of motion:

s = ut + 1/2* (at²)

replacing the variables

8 = (0)(2) + 1/2(a)(2)²

8 = 2a

a = 4 m/s²

Therefore, the acceleration of the block is 4 m/s²

3 0

3 years ago

Which is the best evidence that continents that are now separated were once

Rasek [7]

I’d say It’s B since the plants and fossils are big indicators

3 0

3 years ago

Read 2 more answers

A solenoid is built with 870 turns uniformly distributed over a length of 0.390 m to produce a magnetic field of magnitude 1.00

Y_Kistochka [10]

Answer:

35.7 mA

Explanation:

The magnetic field inside a solenoid is given by:

$B=\mu_0 I n$ (1)

where

$\mu_0 = 4\pi \cdot 10^{-7} H/m$ is the vacuum permeability

I is the current

n is the number of turns per unit length

Since we have

N = 870 turns

L = 0.390 (length of the solenoid)

we can calculate n

$n=\frac{N}{L}=\frac{870}{0.390}=2230.8$

And now we can re-arrange eq.(1) to find the current, I:

$I=\frac{B}{\mu_0 n}=\frac{1.00\cdot 10^{-4} T}{(4\pi\cdot 10^{-7} H/m)(2230.8m^{-1})}=0.0357 A = 35.7 mA$

6 0

3 years ago