NAME First, Mi) 29) A girl throws a rock horizontally, with a velocity of 10 m/s

Question

NAME First, Mi) 29) A girl throws a rock horizontally, with a velocity of 10 m/s, from a bridge. It falls 20 m to the water negligible air resistance? A) 14 m B) 16 m C) 20 m D) 24 m below. How far does the rock travel horizontally before striking the water, assuming 30) A plane has an airspeed of 200 m/s northward, and is in a wind of 50.0 m/s to the west. The plane's speed relative to the ground is A) 150 m/s B) 200 m/s. C) 206 m/s. D) 250 m/s. 31) On a calm day with no wind, you can run a 1500-m race at a velocity of 4.0 m/s. If you run the same race on a day when you have a constant headwind that slows your speed by 2.0 m/s, how much time would it take you to finish the race? A) 250 s B) 750 s C) 1125 s D) 9000 s 32) A boat, whose speed in still water is 8.0 m/s, crosses a river with a current of 6.0 m/s. If the boat heads perpendicular to the current, what is the speed of the boat relative to an observer standing on the shore as it crosses the river? A) 5.3 m/s B) 6.0 m/s C) 8.0 m/s D) 10.0 m/s

Explanation / Answer

Q29 )-

Ux = 10m/s and Uy = 0

then-

Sy = Uy*t +1/2at2

20 = 0 + 1/2 (10)t2

t = 2sec

then

Sx = Ux * t = 20m (In horizontal direction)

Q30)-

there is no component of wind is aline with velocity of plane then the relative velocity of plane become same.

200m/s

Q31)-

time taken to complete the race is-

t = S/v = 1500/4 = 375 sec.

now we have constant headwind then-

time will be 375*2 = 750 sec.

Q32)-

relative velocity would be vector sum of 6m/s and 8m/s, which becomes 10 m/s.

Thank you !!! Have fun

Related Questions

Navigate

• Browse (All)
• Browse N
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.