(6) Wagon B is at rest so it has no momentum at the start. If <em>v</em> is the velocity of the wagons locked together, then
(140 kg) (15 m/s) = (140 kg + 200 kg) <em>v</em>
==> <em>v</em> ≈ 6.2 m/s
(7) False. If you double the time it takes to perform the same amount of work, then you <u>halve</u> the power output:
<em>E</em> <em>/</em> (2<em>t </em>) = 1/2 × <em>E/t</em> = 1/2 <em>P</em>
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The equation to be used here is the trajectory of a projectile as written below:
y = xtanθ +/- gx²/2v²(cosθ)²
where
y is the vertical distance
x is the horizontal distance
θ is the angle of trajectory or launch angle
g is 9.81 m/s²
v is the initial velcity
Since the angle is below horizontal, let's use the minus equation. Substituting the values:
- 0.8 m = xtan15° - (9.81 m/s²)x²/2(4.8 m/s)²(cos15°)²
Solving for x,
x = 2.549 m
However, we only take half of this distance because it was specified that the distance asked before bouncing. Hence, the horizontal distance is equal to 1.27 m.
Answer:
Line 3 has a mistake.
Explanation:
Electromagnetic waves consist of oscillations of electric and magnetic fields that oscillate perpendicular to the each other. Therefore, Line 1 is correct.
Also, the fields in an electromagnetic waves oscillate perpendicular to the direction of propagation of the wave: therefore, they are transverse waves. So Line 2 is also correct.
Electromagnetic waves, contrary to mechanical waves, do not need a medium to propagate: so, they can also travel through a vacuum. Therefore, Line 3 is wrong.
Finally, all electromagnetic waves travel through a vacuum at the same speed, called speed of light:
So, Line 4 is also correct.
Answer:
Magdeburg hemispheres are two half-spheres of equal size. Placing them together traps air between them. This air is merely trapped, and not compressed, so the pressure inside is the same as the pressure of the atmosphere outside the spheres. The spheres thus pull apart with nearly no resistance.
