Answer:
a --> true, b --> false, c --> true, d -->false
Explanation:
a) since it stays floating the gravity force and the upqards push is the same
b) if it's balanced the rocket won't move from the ground, the force of the rocket, has to exceed the force of gravity
c) since it's going in a diretion the force of gravity is exceeding the force pushing it up
d) since that are speeding up at a rate, meaning growing, the force is unbalanced.
Formulated in the 1980s by Robert Sternberg<span>, the </span>triarchic theory<span> distinguishes three aspects of </span>intelligence<span>: analytic skills, such as the ability to think abstractly and evaluate </span>information<span>; creativity, the ability to invent novel solutions or ideas; and practical skills, which enable one to cope with concrete ...</span>
Explanation:
Given that,
A person walks 9.0 km directly east and then turns left and heads directly north for 12.0 km.
We need to find his displacement from the starting position.
We know that,
Displacement = shortest path covered

For direction,

Hence, this is the required solution.
Answer:
The wavelength of these signals is as follow:
- Wavelength of 550 kHz is 545.45 m
- Wavelength of 1600 kHz is 187.5 m
Explanation:
Given that:
Frequency = 550 kHz & 1600 kHz
Velocity = 3.0 x 10⁸ m/s
As we know that frequency is expressed by the following equation:
- Frequency = Velocity / Wavelength ---- (1)
For 550 kHz:
The equation can be rearranged as
Wavelength = Velocity / Frequency
Wavelength = (3.0 x 10⁸ m/s) / (550 x 1000 Hz)
Wavelength = 545.45 m
For 1600 kHz:
Wavelength = Velocity / Frequency
Wavelength = (3.0 x 10⁸ m/s) / (1600 x 1000 Hz)
Wavelength = 187.5 m
Answer:
a) Em₀ = 42.96 104 J
, b)
= -2.49 105 J
, c) vf = 3.75 m / s
Explanation:
The mechanical energy of a body is the sum of its kinetic energy plus the potential energies it has
Em = K + U
a) Let's look for the initial mechanical energy
Em₀ = K + U
Em₀ = ½ m v2 + mg and
Em₀ = ½ 50.0 (1.20 102) 2 + 50 9.8 142
Em₀ = 36 104 + 6.96 104
Em₀ = 42.96 104 J
b) The work of the friction force is equal to the change in the mechanical energy of the body
= Em₂ -Em₀
Em₂ = K + U
Em₂ = ½ m v₂² + m g y₂
Em₂ = ½ 50 85 2 + 50 9.8 427
Em₂ = 180.625 + 2.09 105
Em₂ = 1,806 105 J
= Em₂ -Em₀
= 1,806 105 - 4,296 105
= -2.49 105 J
The negative sign indicates that the work that force and displacement have opposite directions
c) In this case the work of the friction going up is already calculated in part b and the work of the friction going down would be 1.5 that job
We have that the work of friction is equal to the change of mechanical energy
= ΔEm
= Emf - Emo
-1.5 2.49 10⁵ = ½ m vf² - 42.96 10⁴
½ m vf² = -1.5 2.49 10⁵ + 4.296 10⁵
½ 50.0 vf² = 0.561
vf = √ 0.561 25
vf = 3.75 m / s