Answer:
a = - 1.47 [m/s²], descending or going down
Explanation:
To solve this problem we must use Newton's second law which tells us that the sum of forces on a body is equal to the product of mass by acceleration.
∑F = m*a
where:
∑F = Forces applied [N]
m = mass = 10 [kg]
a = acceleration [m/s²]
Let's assume the direction of the upward forces as positive, just as if the movement of the box is upward the acceleration will be positive.
By performing a summation of forces on the vertical axis we obtain all the required forces and other magnitudes to be determined.

where:
g = gravity acceleration = 9.81 [m/s²]
N = normal force measured by the scale = 83.4 [N]
Now replacing:
![-(10*9.81)+83.4=10*a\\-14.7=10*a\\a=-1.47[m/s^{2} ]](https://tex.z-dn.net/?f=-%2810%2A9.81%29%2B83.4%3D10%2Aa%5C%5C-14.7%3D10%2Aa%5C%5Ca%3D-1.47%5Bm%2Fs%5E%7B2%7D%20%5D)
The acceleration has a negative sign, this means that the elevator is descending at that very moment.
Answer:
100 m/s
Explanation:
here we use the wave equation which states that the velocity is equal to the product of the frequency and the wavelength.
so v = 50 × 2
v = 100 m/s
Answer:
The initial angular speed of the CD is equal to 14.73 rad/s.
Explanation:
Given that,
Angular displacement, 
Final angular speed, 
The acceleration of the CD,
We need to find the initial angular speed of the CD. Using third equation of kinematics to find it such that,

Put all the values,

So, the initial angular speed of the CD is equal to 14.73 rad/s.
Answer:
Radiation
Explanation:
Radiation refers to the emission of energy in rays or waves
Answer:
V1 = ____0.3______ m/s, V2 = ____-0.3______ m/s,
p1 = ____0.015______ kg m/s, p2 = ___-0.015_______ kg m/s,
ptotal = _0___________ kg m/s
Explanation:
Taking the marble ball that moves from right to left as Marble 1 and the one that moves from left to right as Marble 2. We take direction from left to right as negative and from right to left as positive. Therefore, velocity of marble 1 will be +0.3 m/s while velocity of marble 2 will be -0.3 m/s. The mass of marble 1, m2 0.05 Kg and same to marble 2, m2=0.05 Kg
Momentum is product of mass and velocity hence using p to represent momentum
P1=0.05*0.3=0.015 Kg m/s
P2=0.05*-0.3=-0.015 Kg m/s
V1=0.3 m/s, V2=-0.3 m/s
The total momentum before collision will be the sum of P1 and P2 hence 0.015 Kg m/s+-0.015 Kg m/s=0
Ptotal=0 Kg m/s