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:
1.41 m/s, 7.85 rad/s
Explanation:
We can start by calculating the tangential velocity, which is given by:
where
r = 18 cm = 0.18 m is the radius of the circumference
T = 0.8 s is the period
Substituting,
Now we can also calculate the angular velocity, which is given by:
where again,
T = 0.8 s is the period
Substituting,
Answer:
4.29 millimeters
Explanation:
Bats emit ultrasound waves: in air, ultrasound waves travel at a speed of
The frequency of the waves emitted by this bat is:
Therefore we can find the wavelength of the wave emitted by the bat by using the relationship between speed, frequency and wavelength:
<span>B. Energy is never created nor destroyed.
</span>
Answer:
19 800 lbm of carbon dioxide more.
Explanation:
<u>Taurus</u>
Amount of gasoline used in 5 years = 650 ga/year * 5 years = 3250 ga
amount of carbon dioxide released = 19.8 lbm/ga * 3250 ga = 64 350 lbm
<u>Explorer</u>
Amount of gasoline used in 5 years = 850 ga/year * 5 years = 4250 ga
amount of carbon dioxide released = 19.8 lbm/ga * 4250 ga = 84 150 lbm
Extra amount of CO2 released = 84 150 lbm - 64 350 lbm = 19 800 lbm
