Answer:
D) 24m, 300o
Explanation:
The vector A has magnitude of 12 m and it makes 120 degree with + ve x axis
So it can be represented by the vector as follows
A = 12 Cos 120 i + 12 sin 120 j
vector 2A = 24 Cos 120 i + 24 sin 120 j
- 2A = - 24 Cos 120 i - 24 sin 120 j
= 24 Cos ( 180 -120 ) - 24 sin ( 180 -120)
= 24 Cos 60 - 24 sin 60
= 24 Cos ( 360 - 60 ) + 24 sin ( 360 -60 )
= 24 Cos 300 + 24 sin 300
It represents a vector having magnitude of 24 and making 300 degree with + ve x- axes in anticlockwise direction.
Answer:
a The larger football player will move, but because of his larger mass, his velocity will be much slower than the smaller player
Explanation:
When the collision takes two equal and opposite forces are created at the point of collision . The force created on the bigger mass will force it to accelerate and the force on moving smaller mass will force it to slow down .
Because of bigger mass , acceleration on bigger mass will be less and hence its velocity will be less .
Hence option a is the right answer.
Answer:
28000 newtons
Explanation:
Force = mass x acceleration
= 7000 * 4
=28000
Unit for force is Newtons
Answer:
The rule for kilometers is that every three seconds between a lightning flash and the following thunder gives the distance to the flash in kilometers.
Explanation:
In order to use the rule of thumb to find the speed of sound in meters per second, we need to use some conversion ratios. We know there is 1 mile per every 5 seconds after the lightning is seen. We also know that there are 5280ft in 1 mile and we also know that there are 0.3048m in 1ft. This is enough information to solve this problem. We set our conversion ratios like this:
notice how the ratios were written in such a way that the units got cancelled when calculating them. Notice that in one ratio the miles were on the numerator of the fraction while on the other they were on the denominator, which allows us to cancel them. The same happened with the feet.
The problem asks us to express the answer to one significant figure so the speed of sound rounds to 300m/s.
For the second part of the problem we need to use conversions again. This time we will write our ratios backwards and take into account that there are 1000m to 1 km, so we get:
This means that for every 3.11s there will be a distance of 1km from the place where the lightning stroke. Since this is a rule of thumb, we round to the nearest integer for the calculations to be made easily, so the rule goes like this:
The rule for kilometers is that every three seconds between a lightning flash and the following thunder gives the distance to the flash in kilometers.
Answer:
High Points = Crest
Low Points = Troughs
Explanation: