Ahhhh, thanks a lot man, appreciate it. If you wouldn't mind helping me with a couple more (if you can ):
Bob and Bill both swim at 0.50 km/h. They start beside a river 015 km wider with a current of 0.30 km/h. Bob swims 150 m directly downstream, then turns around and swims back to his original spot.
Bill swims to a tree directly across the river, then turns around and swims back to the original spot. How long does each person take to complete their trips? (0.94 h, and 0.75 h)
Answers are given but they seem so random. For example, Bill is swimming straight across which is a distance of 0.15 km, and his speed is given. How come it doesn't work to find the time it takes him to swim across (delta d / v) and multiply by 2 to account for his return trip??
A boy throws newspaper sideways onto porches of customer while riding his bike, which is 15 m in front of the porches. The boy throws the papers at a horizontal speed of 6.0 m/s relative to himself and rides the bike at a speed of 4.0 m/s relative to the sidewalk.
How far in advance of a porch should he throw a paper so it lands on target? (10 m)
If he waits until he is directly opposite a porch, at what horizontal angle with respect to the sidewalk will he have to throw the paper to hit the porch? (48.2 degrees)
I have no idea how to solve this one. Should I first find the speed with which the papers travel relative to the ground? And will this even help?????
Bob and Bill both swim at 0.50 km/h. They start beside a river 015 km wider with a current of 0.30 km/h. Bob swims 150 m directly downstream, then turns around and swims back to his original spot.
Bill swims to a tree directly across the river, then turns around and swims back to the original spot. How long does each person take to complete their trips? (0.94 h, and 0.75 h)
Answers are given but they seem so random. For example, Bill is swimming straight across which is a distance of 0.15 km, and his speed is given. How come it doesn't work to find the time it takes him to swim across (delta d / v) and multiply by 2 to account for his return trip??
A boy throws newspaper sideways onto porches of customer while riding his bike, which is 15 m in front of the porches. The boy throws the papers at a horizontal speed of 6.0 m/s relative to himself and rides the bike at a speed of 4.0 m/s relative to the sidewalk.
How far in advance of a porch should he throw a paper so it lands on target? (10 m)
If he waits until he is directly opposite a porch, at what horizontal angle with respect to the sidewalk will he have to throw the paper to hit the porch? (48.2 degrees)
I have no idea how to solve this one. Should I first find the speed with which the papers travel relative to the ground? And will this even help?????