Answer:
8428
Step-by-step explanation:
According to the Question,
- Given, A theater has 56 rows of seats. If there are 13 seats in the first row, 18 in the 2nd row, 23 in the 3rd row.
We have a number sequence 13, 18, 23, ...
- We can say that this is an arithmetic sequence because of the common difference 'd', is equal to 5, and the first term 'a1' is equal to 13.
- The formula for the sum of an arithmetic sequence with n terms is given is
![S_n= \frac{n}{2} [2a_1+(n-1)d]S](https://tex.z-dn.net/?f=S_n%3D%20%5Cfrac%7Bn%7D%7B2%7D%20%5B2a_1%2B%28n-1%29d%5DS)
.
Substitute the given values into the equation to solve for the sum of the 56 rows of seats.
![S_56= \frac{56}{2}[2(13)+(56-1)(5)]\\S_{56}=28\left[26+275\right]\\S_{56}=28\left[301\right]\\S_{56}=8428](https://tex.z-dn.net/?f=S_56%3D%20%5Cfrac%7B56%7D%7B2%7D%5B2%2813%29%2B%2856-1%29%285%29%5D%5C%5CS_%7B56%7D%3D28%5Cleft%5B26%2B275%5Cright%5D%5C%5CS_%7B56%7D%3D28%5Cleft%5B301%5Cright%5D%5C%5CS_%7B56%7D%3D8428)
Therefore, there are 8428 seats in all.
C. Negative because since the neutral atom stands at 0 and positive ions are 1+ and electrons are negative if it gains the electron ( negative ) it will become negative.
Answer:
- 0.100
Step-by-step explanation:
Length of the ladder, H = 6 m
Distance at the bottom from the wall, B = 1.3 m
Let the distance of top of the ladder from the bottom at the wall is P
Thus,
from Pythagoras theorem,
B² + P² = H² .
or
B² + P² = 6² ..............(1) [Since length of the ladder remains constant]
at B = 1.3 m
1.3² + P² = 6²
or
P² = 36 - 1.69
or
P² = 34.31
or
P = 5.857
Now,
differentiating (1)
at t = 2 seconds
change in B = 0.3 × 2= 0.6 ft
Thus,
at 2 seconds
B = 1.3 + 0.6 = 1.9 m
therefore,
1.9² + P² = 6²
or
P = 5.69 m
on substituting the given values,
2(1.9)(0.3) + 2(5.69) × 
= 0
or
1.14 + 11.38 × = 0
or
11.38 × = - 1.14
or
= - 0.100
here, negative sign means that the velocity is in downward direction as upward is positive
