Scientific knowledge builds upon previous knowledge."

A4 40 kg girl skates at 3.5 m/s one ice toward her 65 kg friend who is standing still, with open arms. As they collide and hold

salantis [7]

Explanation:

Below is an attachment containing the solution.

8 0

2 years ago

An airplane flying at constant air speed from Indianapolis to St. Louis (assume they are directly east-west of each other) in ca

irga5000 [103]

Answer:

Explanation:

Suppose the distance between the two cities is D and the velocity in calm weather is V . The total time taken in two way travel is given by

Total distance / velocity

= 2 D / V

Suppose velocity of wind is v . Then in one way the velocity of airplane will become V + v and in the return trip its velocity will be V - v

Total time taken

= $\frac{D}{V+v} +\frac{D}{V-v}$

= $\frac{2DV}{V^2-v^2}$

= $\frac{2V^2D}{V(V^2-v^2)}$

= $\frac{2D}{V(1 - \frac{v^2}{V^2}) }$

= The denominator contains a factor

$1-\frac{v^2}{V^2}$

which is less than one so time calculated will be more than

2D / V

Hence in the second case time taken will be more .

7 0

2 years ago

The U.S. Department of Energy had plans for a 1500-kg automobile to be powered completely by the rotational kinetic energy of a

navik [9.2K]

Answer:

230

Explanation:

$\omega$ = Rotational speed = 3600 rad/s

I = Moment of inertia = 6 kgm²

m = Mass of flywheel = 1500 kg

v = Velocity = 15 m/s

The kinetic energy of flywheel is given by

$K=\dfrac{1}{2}I\omega^2\\\Rightarrow K=\dfrac{1}{2}6\times 3600^2\\\Rightarrow K=38880000\ J$

Energy used in one acceleration

$K=\dfrac{1}{2}mv^2\\\Rightarrow K=\dfrac{1}{2}1500\times 15^2\\\Rightarrow K=168750\ J$

Number of accelerations would be given by

$n=\dfrac{38880000}{168750}\\\Rightarrow n=230.4$

So the number of complete accelerations is 230

8 0

2 years ago

A harmonic wave travels in the positive x direction at 6 m/s along a taught string. A fixed point on the string oscillates as a

Lapatulllka [165]

Answer:

Amplitude, A = 0.049 meters

Explanation:

Given that,

A harmonic wave travels in the positive x direction at 6 m/s along a taught string. A fixed point on the string oscillates as a function of time according to the equation :

$y = 0.049 \cos(7t)$ .......(1)

The general equation of a wave is given by :

$y=A\cos(\omega t)$ .......(2)

A is amplitude of wave

On comparing equation (1) and (2) we get :

A = 0.049 meters

So, the amplitude of the wave is 0.049 meters.

3 0

2 years ago

Is it possible for two pieces of the same metal to have different recrystallization temperatures? Is it possible for recrystalli

Butoxors [25]

Answer:

Explained

Explanation:

Two pieces of the same metal can have different recrystallization temperatures if the pieces have been cold worked to different amounts. The piece of work cold worked to greater extend will have more internal energy to drive the recrystalline process and lower recrystallization temperature.

Yes, its possible that recrystallization to take place in some regions of a part before it does in other regions of the same part if the work has been unevenly strained or if the part have different thickness at different sections.

6 0

2 years ago