Temperance asked: Sorry, but I don’t want a speech saying how I shouldn’t get others to do my work. I have been sick and forced to stay home 2 weeks. Now I’m working my butt off to catch up. I had literally like 100 problems for Physics but only could answer about 80%.
If you can answer some, thank you!! And it would be much appreciated if there could be an explaination so I may learn also. If you don’t know some, it’s okayyy. (: But every little bit can help me. <3
1.) A swimmer is heading directly across a river 200m wide reaches the opposite bank in 6min 40s. She is swept downstream 300m. How fast can she swim in still water?
2.)The driver of a motorboat that that can move at 10m/s wishes to travel directly across strait in which the current flows at 5m/s. (a) At what angle upstream should the driver head the boat? (b) How long will it take to cross a distance of 1.6km?
3.) 3 forces, each havin magnitude of 30lbs, pull an object 120 degrees apart from each other. Which is true?
a. resultant force is 0.
b. resultant force is greater 30lb
c. resultant force 30lb
4.) Two vectors, R & S are R: north. & S: east. If the vector S is subtracted from vector R, then the vector T=R-S is which? SE, SW, NE, NW?
5.) Your motorboat can move at 30km/h in still water. How much time will it take you to move 12km upstream, in a river flowing at 6km/h?
6.)Bullet G is dropped, from rest, at the same time that another bullet H is fired horizontally from a rifle. If both bullets leave the same height above the ground, then...
a. G hits before H
b. both at the same time
c. H hits before G
d. not enough info
7.) Suppose that several projectiles are fired upward. Which one will be in the air longest?
a. farthest range, R
b. highest max elevation, h
c. one which has product of Rth is max
d. greatest initial velocity
8.) A golf ball is hit w/initial velocity of 60m/s at an angle of 130 degrees above the horizontal. How far does it travel?
9.) A plane flying horizontally at a speed of 50m/s and at an elevation of 160m drops a package of supplies. Two seconds later it drops a second package. How far apart will the two packages land on the ground?
10.) At what angle should a water-gun be aimed in order for the water to land with the greatest horizontal range? O or 30 or 45 or 90?
11.) A girl throws a stone straight down from a bridge. The stone leaves her hand w/velocity of 8m/s at height of 12m above the water. How much time does it take for the stone to hit the water?
12.) You hit a tennis ball over the net. When the ball reaches it's max height, its speed is...
a. zero.
b. less than initial
c. equal to initial
d. greater than initial
13.) You are serving the volleyball for the 2nd time in a game. If the ball leaves your hand with twice the velocity it had on your 1st serve, its horizontal range would be...
a. two times as much
b. half as much
c. twice as much
d. four times as much
14.) A soccerball is kicked w/velocity of 25m/s at an angle of 45 degrees above the horizontal. What is the vertical component as it travels along trajectory? (Neglect air friction)
a. zero
b. g downward
c. g sin (45 degrees) upward
d. g upward
e. g cos (45 degrees) downward
15.) A ball thrown horizontally from a point 24m above the ground, strikes the ground after traveling horizontally a distance of 18m. With what speed was it thrown? (g= 10m/s^2)
16.) A rifle bullet is fired at an angle of 30 degrees below the horizontal w/initial velocity of 800m/s from the top of the cliff 80m high. How far from the base of the cliff does it strike the level ground below?
17.) A mortar shell is launched with a velocity of 100m/s at an angle of 30 degrees above horizontal from a point on a cliff 50m above a level plain below. How far from the base of the cliff does the mortar shell strike the ground?
18.) An Olympic athlete throw a javelin at 4 different angles above the horizontal, each with the same speed: 30, 40, 60, & 80 degrees. Which 2 throws cause the javelin to land the same distance?
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