Answer:
309 m
Explanation:
time apart = 0.8 s
speed of sound in air = 343 m/s
speed of sound in concrete = 3000 m/s
lets assume it time it takes to travel trough concrete = T
the time it takes to travel through air = T + 0.8 since they are 0.8 s apart
the distance traveled by both waves is the same, so we can equate the distance for both waves
distance = speed x time
- for concrete, distance = 3000 x T
- for air, distance = 343 x (T + 0.8)
now equating the two distance together we have
3000 x T = 343 x (T + 0.8)
3000T = 343T + 274.4
3000T - 343T = 274.4
T = 0.103 s
recall that distance = 3000 x T = 3000 x 0.103 = 309 m
Answer: only the third option. [Vector A] dot [vector B + vector C]
The dot between the vectors mean that the operation to perform is the "scalar product", alson known as "dot product".
This operation is only defined between two vectors, not one scalar and one vector.
When you perform, in the first option, the dot product of any ot the first and the second vectors you get a scalar, then you cannot make the dot product of this result with the third vector.
For the second option, when you perform the dot product of vectar B with vector C you get a scalar, then you cannot make the dot product ot this result with the vector A.
The third option indicates that you sum the vectors B and C, whose result is a vector and later you make the dot product of this resulting vector with the vector A. Operation valid.
The fourth option indicates the dot product of a scalar with the vector A, which we already explained that is not defined.
Answer:
Displacement is a vector quantity that refers to "how far out of place an object is"; it is the object's overall change in position.
Answer:
100 Watts
Explanation:
<u>These equations are needed to work out the answer:</u>
- power= work done/ time taken
- work done= force* distance
- force= mass* acceleration
force: 10 kg* 2m/s= 20
work done: 20* 10m=200
power: 200/2=100
I think the answer is (C.) but im not sure
