Answer:
1.53 s
Explanation:
Initially vertical component of velocity of the ball, uy = 7.5 m/s
Net displacement is vertical direction is zero, Δy =0
Use second equation of motion:
Δy = uy t + 0.5 a t²
Here, acceleration a = -g (g =9.8 m/s²)
Substitute all the values and solve for g
0 = 7.5 t -0.5 (9.8)t²
7.5 t = 4.9 t²
t = 1.53 s
Answer:
1.37 rad/s
Explanation:
Given:
Total length of the tape is,
m
Total time of run is,
hours
We know, 1 hour = 3600 s
So, 2.1 hours = 2.1 × 3600 = 7560 s
So, total time of run is,
s
Inner radius is, 
Outer radius is, 
Now, linear speed of the tape is, 
Let the same angular speed be
.
Now, average radius of the reel is given as the sum of the two radii divided by 2.
So, average radius is, 
Now, common angular speed is given as the ratio of linear speed and average radius of the tape. So,

Therefore, the common angular speed of the reels is 1.37 rad/s.
Answer:
96%
Explanation:
To find the values of the motor efficiency you use the following formula:

P_o: output power = 864J/0.5min=864J/30s=28.8W
P_i: input power = I*V = (3A)(12V) = 36W
By replacing this values you obtain:

hence, the motor efficiency is about 96%
traslation:
Pentru a găsi valorile eficienței motorului, utilizați următoarea formulă:
P_o: putere de ieșire = 864J / 0.5min = 864J / 30s = 28.8W
P_i: putere de intrare = I * V = (3A) (12V) = 36W
Înlocuind aceste valori obțineți:
prin urmare, eficiența motorului este de aproximativ 96%
Answer: the options to the questions are
a. 1.0 moles of N2
b.0.5 moles of New
c.0.2 moles of CO2
d.2 moles of He
Answer D
Explanation:
The average molecular speed v of gas is given by =√(8RT,/πM)
From the equation it can be seen that substance with lowest molar mass has the highest velocity has He is the answer