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Karolina [17]
3 years ago
9

Calculate the average speed of an automobile that travels 60km east and then 80km north in two hours

Physics
1 answer:
lbvjy [14]3 years ago
8 0
We need to calculate speed , so we don't need to consider direction.
speed =distance/time
=(80+60)/2
=70.

But if we were to calculate velocity,we would need to consider the direction.
The direction of resultant displacement would be in north east direction with displacement
=√60^2 +80^2
=100km

The average velocity=100/2=50kmph
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7. A cube sits in the Cartesian coordinate system. Each side of the cubeis 2m. Electric charge is distributed in the cube with a
Zanzabum

Answer:

Net charge inside the cube is 321.6 C

Explanation:

Given charge density function is ρ = xy^2 e^{2z}

side of cube is 2m

According to the definition of volume charge density total charge is given by

q = total charge = \int {\rho} \, dv where dv = dxdydz is the volume element

on substututing the respected values we get

q = \int\limits^2_0 {x} \, dx \int\limits^2_0 {y^2} \, dy \int\limits^2_0 {e^2^z} \, dz  

on solving the above integration we get

q =  \frac{x^2}{2} x \frac{y^3}{3} x \frac{e^2^z}{2}

⇒ q = 321.6 C

Therefore net charge inside the cube is 321.6 C

4 0
2 years ago
A disk with mass 1.64 kg and radius 0.61 meters is spinning counter-clockwise with an angular velocity of 17.6 rad/s. A rod of m
Masja [62]

Answer:

The loss in rotational kinetic energy due to the collision is 36.585 J.

Explanation:

Given;

mass of the disk, m₁ = 1.64 kg

radius of the disk, r = 0. 61 m

angular velocity of the disk, ω₁ = 17.6 rad/s

mass of the rod, m₂ = 1.51 kg

length of the rod, L = 1.79 m

angular velocity of the rod, ω₂ =  5.12 rad/s (clock-wise)

let the counter-clockwise be the positive direction

let the clock-wise be the negative direction

The common final velocity of the two systems after the collision is calculated by applying principle of conservation of angular momentum ;

m₁ω₁  + m₂ω₂ = ωf(m₁ + m₂)

where;

ωf is the common final angular velocity

1.64 x 17.6    + 1.51(-5.12) = ωf(1.64 + 1.51)

21.1328 = ωf(3.15)

ωf = 21.1328 / 3.15

ωf = 6.709 rad/s

The moment of inertia of the disk is calculated as follows;

I_{disk} = \frac{1}{2} mr^2\\\\I_{disk}  = \frac{1}{2} (1.64)(0.61)^2\\\\I_{disk}  = 0.305 \ kgm^2

The moment of inertia of the rod about its center is calculated as follows;

I_{rod} = \frac{1}{12} mL^2\\\\I_{rod} = \frac{1}{12} \times 1.51 \times 1.79^2\\\\I _{rod }= 0.4032\ kgm^2

The initial rotational kinetic energy of the disk and rod;

K.E_i = \frac{1}{2} I_{disk}\omega _1 ^2 \ \ + \ \  \frac{1}{2} I_{rod}\omega _2 ^2 \\\\K.E_i=  \frac{1}{2} (0.305)(17.6) ^2 \ \ + \ \  \frac{1}{2} (0.4032)(-5.12) ^2\\\\K.E_i = 52.523 \ J

The final rotational kinetic energy of the disk-rod system is calculated as follows;

K.E_f = \frac{1}{2} I_{disk}\omega _f ^2 \ \ + \ \  \frac{1}{2} I_{rod}\omega _f ^2\\\\K.E_f = \frac{1}{2} \omega _f ^2(I_{disk} + I_{rod})\\\\K.E_f = \frac{1}{2} (6.709) ^2(0.305+ 0.4032)\\\\K.E_f = 15.938 \ J

The loss in rotational kinetic energy due to the collision is calculated as follows;

\Delta K.E = K.E_f \ - \ K.E_i\\\\\Delta K.E = 15.938 J  \ - \ 52.523 J\\\\\Delta K.E = - 36.585 \ J

Therefore, the loss in rotational kinetic energy due to the collision is 36.585 J.

8 0
2 years ago
As your hand moves back and forth to generate longitudinal pulses in a spiral spring, your hand completes 2.91 back-and-forth cy
Lapatulllka [165]

Answer:

Wavelength, \lambda=0.011\ m

Explanation:

Given that,

Number of cycles in a spiral spring is 2.91 in every 3.67 s

The velocity of the pulse in the spring is 0.925 cm/s, v = 0.00925 m/s

To find,

Wavelength

Solution,

Number of cycles per unit time is called frequency of a wave. The frequency of the longitudinal pulse is,

f=\dfrac{2.91}{3.67}=0.79\ Hz

The wavelength of a wave is given by :

\lambda=\dfrac{v}{f}

\lambda=\dfrac{0.00925\ m/s}{0.79\ Hz}

\lambda=0.011\ m

So, the wavelength of the longitudinal pulse is 0.011 meters. Hence, this is the required solution.

8 0
2 years ago
The difference in energy on either side of the wheel is a measure of the wheel’s ___________.
atroni [7]
I believe the answer is potential difference
3 0
2 years ago
Is there a frame of reference one can go into that seems to eliminate gravity as Newton described it?
andriy [413]

Answer:

Yes such a frame exists: a free-fall (free-float frame) frame. This frame of reference is subject only to gravity and no forces such as electromagnetic forces or nuclear forces.

3 0
3 years ago
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