1) A car travels at 50.0 km/hr for 2.00 hours. It then travels an additional dis

Question

1) A car travels at 50.0 km/hr for 2.00 hours. It then travels an additional distance of 40.0 km in 1.00 hour. The average speed of the car for the entire trip is
A) 61.0 km/hr.
B) 57.1 km/hr.
C) 53.3 km/hr.
D) 46.7 km/hr.
E) 30.0 km/hr.

2) A car starts from rest at t = 0 and accelerates in a straight line with a constant acceleration until t = 3.0 s. The distance traveled between t = 1.0 s and t = 2.0 s is
A) four time the distance traveled during the first second.
B) three times the distance traveled during the first second.
C) two times the distance traveled during the first second.
D) the same as the distance traveled during the first second.

Explanation / Answer

1.) The proper way to do it is to find the total km traveled. In 2 hrs. 50*2 = 100 km In 1 hr. 40*1 = 40 km 140 km in 3 hours. speed = distance/time = 140/3 = 46.7 km/hr. choice D. 2.) d = v0 + (1/2)a*t^2 v0 = 0 since the car starts from rest. In 1 s, it travels: d = (1/2)(a) = 0.5a in 2s, it travels: d = (1/2)(a)4 = 2a In 3s, it travels: d = (1/2)(a)9 = 4.5a Between 1 and 2 seconds the car travels: 2a - 0.5a = 1.5a Between 0 and 1s, the car travels: 0.5a 1.5a/0.5a = 3 The car travels 3 times the distance: choice B

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

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