A boat moves through the water in a river at a speed of 8 m/s relative to the water. The boat makes a trip downstream and then makes a return trip upstream to the original starting place. Which trip takes longer?
a. the downstream trip
b. the upstream trip
c. Both trips take the same amount of time.
d. The answer cannot be figured without knowing the speed of the river flow.
[Ques. 2] A river flows due east at 2.0 m/s. A boat crosses the 300-m-wide river by maintaining a constant velocity of 15 m/s due north relative to the water. If no correction is made for the current, how far downstream does the boat move by the time it reaches the far shore?
a. 80 m
b. 30 m
c. 25 m
d. 40 m
e. 50 m
[Ques. 3] A boat moves at 10.8 m/s relative to the water. If the boat is in a river where the current is 2.00 m/s, how long does it take the boat to make a complete round trip of 1 100 m upstream followed by a 1 100-m trip downstream?
a. 250 s
b. 172 s
c. 211 s
d. 297 s
e. 336 s
[Ques. 4] A jet airliner moving at 470 mph due east moves into a region where the wind is blowing at 110 mph in a direction 30.0 north of east. What is the new velocity and direction of the aircraft?
a. 568 mph, 5.56 N of E
b. 573 mph, 5.98 N of E
c. 520 mph, 9.06 N of E
d. 568 mph, 10.4 N of E
e. 448 mph, 9.45 N of E
[Ques. 5] A projectile is fired directly upwards at 49.4 m/s. A second projectile is dropped from rest at some higher elevation at the instant the first projectile is fired and passes the first projectile 3.00 s later. From the frame of reference of the first projectile, what is the velocity of the second projectile as it passes by?
a. 64.1 m/s, downward
b. 71.5 m/s, downward
c. 49.4 m/s, downward
d. 34.7 m/s, downward
e. 104 m/s, downward
[Ques. 6] What is the magnitude of the horizontal displacement of the rock?
a. 3.53 m
b. 13.3 m
c. 222 m
d. 26.1 m
[Ques. 7] What is the speed of the rock as it hits the ground?
a. 11.5 m/s
b. 26.8 m/s
c. 24.5 m/s
d. 16.2 m/s
[Ques. 8] What is the magnitude of the horizontal-velocity component of the rock as it hits the ground?
a. 79.5 m/s
b. 8.81 m/s
c. 58.7 m/s
d. 7.39 m/s
[Ques. 9] What is the magnitude of the vertical-velocity component of the rock as it hits the ground?
a. 8.81 m/s
b. 7.39 m/s
c. 25.8 m/s
d. 19.3 m/s
[Ques. 10] A projectile is launched at an angle less than 30 and at speed v. Which will increase the projectile's range more, ignoring atmospheric drag?
a. doubling the launch angle b. increasing the speed of launch by 50
c. reducing the mass of the projectile d. launching on February 29th
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