a. A car driving in a straight line at 20 m/s.
Explanation:
An object is in a state of equilibrium when no force is acting upon it. There are two types of equilibrium; static equilibrium and dynamic equilibrium.
Static equilibrium is a state when a body is at rest.
Dynamic equilibrium is an equilibrium state when a body is moving at a constant velocity. (Rectilinear Motion).
A car moving in a straight line at 20 m/s has a constant velocity and hence no force is acting on it. So, it is in dynamic equilibrium.
A book sitting on a table without moving is not is dynamic equilibrium but in static equilibrium.
A boy jumping off a diving board in not in equilibrium as gravitational force is acting upon him and he has a changing velocity.
A motorcycle going in a circle at a constant speed has changing velocity because the direction of the motion is constantly changing hence it is not in the state of motion.
Keywords: velocity, force, equilibrium, static equilibrium, dynamic equilibrium
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Answer:
F=(-4.8*10^22,0,0) N
Explanation:
<u>Given :</u>
We are given the magnitude of the momentum of the planet and let us call this momentum (p_now) and it is given by p_now = 2.60 × 10^29 kg·m/s. Also, we are given the force exerted on the planet F = 8.5 × 10^22 N. and the angle between the planet and the star is Ф = 138°
Solution :
We are asked to find the parallel component of the force F The momentum here is not constant, where the planet moving along a curving path with varying speed where the rate change in momentum and the force may be varying in magnitude and direction. We divide the force here into two parts: a parallel force F to the momentum and a perpendicular force F' to the momentum.
The parallel force exerted to the momentum will speed or reduce the velocity of the planet and does not change its moving line. Let us apply the direction cosines, we could obtain the parallel force as next
F=|F|cosФp (1)
Where the parallel force F is in the opposite direction of p as the angle between them is larger than 90°. Now we can plug our values for 0 and I F I into equation (1) to get the parallel force to the planet
F=|F|cosФp
=-4.8*10^22 N*p
<em>As this force is in one direction, we could get its vector as next </em>
F=(-4.8*10^22,0,0) N
F=(0,-4.8*10^22,0) N
F=(0,0-4.8*10^22) N
The cosine of 138°, the angle between F and p is, is a negative number, so F is opposite to p. The magnitude of the planet's momentum will decrease.
Answer:
The person's ear canal length is 2.91 cm.
Explanation:
Given that,
Frequency = 3000 Hz
Temperature = 30°C
We need to calculate the speed
Using equation of sound wave with temperature
[texs]v(t)=331+0.6\times T[/tex]
Put the value of T
We need to calculate the length
Using formula of closed organ pipe
Where, L = length
v = velocity
f = frequency
Put the value into the formula
Hence, The person's ear canal length is 2.91 cm.
