- #1
victorhugo
- 127
- 5
"A cricket ball moving at 4m/s south, is hit over square leg which is due west at 3m/s, what is the change in velocity?"
The change in velocity ΔV= V-U (where V= final velocity and U= initial velocity)
The way I was shown is to add negative U to V, which would give us the same triangle and wouldn't change the answer(change in displacement is still 5m) so I believe the answer is just 3m/s-4m/s= -1m/s
For the second question:
"A plane is heading due north at 120m/h (Im assuming the teacher made a mistake and it is km/h because 120 m/h is extremely slow)in an easterly crossswind of 50km/h. What direction does the plane have to fly to end up flying due north?"
My attempt:
I haven't been shown how to do this, but I am assuming that the plane needs to fly north east, at an angle greater than what it is now, and i believe we can get the angle now by using SOH CAH TOA:
tan=opp./adj. (wind at 50km/h is opposite and the 120km/h north is the adjacent) to the angle is tan^-1(50/120) = 22.6 degrees.
Now to find at what direction the plane must fly to cancel the 50km/h easterly wind, i don't know. Even if I were to add negative 50 to 120 in a graph, the angle would be the same... I would appreciate a hint!
For the third question:
"If a car traveling south at 50km/h rounds a bend and travels east at the same speed. What is its change in velocity?"
ΔV=V-U = 50-50 = 0m/s
No change in velocity.
Fourth and last question:
Just like question 2, I have no idea how to find the angle it should point to. If someone could give me a hint, woudl highly appreciate it :)
The change in velocity ΔV= V-U (where V= final velocity and U= initial velocity)
The way I was shown is to add negative U to V, which would give us the same triangle and wouldn't change the answer(change in displacement is still 5m) so I believe the answer is just 3m/s-4m/s= -1m/s
For the second question:
"A plane is heading due north at 120m/h (Im assuming the teacher made a mistake and it is km/h because 120 m/h is extremely slow)in an easterly crossswind of 50km/h. What direction does the plane have to fly to end up flying due north?"
My attempt:
I haven't been shown how to do this, but I am assuming that the plane needs to fly north east, at an angle greater than what it is now, and i believe we can get the angle now by using SOH CAH TOA:
tan=opp./adj. (wind at 50km/h is opposite and the 120km/h north is the adjacent) to the angle is tan^-1(50/120) = 22.6 degrees.
Now to find at what direction the plane must fly to cancel the 50km/h easterly wind, i don't know. Even if I were to add negative 50 to 120 in a graph, the angle would be the same... I would appreciate a hint!
For the third question:
"If a car traveling south at 50km/h rounds a bend and travels east at the same speed. What is its change in velocity?"
ΔV=V-U = 50-50 = 0m/s
No change in velocity.
Fourth and last question:
Just like question 2, I have no idea how to find the angle it should point to. If someone could give me a hint, woudl highly appreciate it :)