Physics question!!? I need help?

Question

A motorist drives north for 34.0 minutes at 66.0 km/h and then stops for 15.0 minutes. He then continues north, traveling 130 km in 2.10 h.

a) What is his total displacement? (km)

(b) What is his average velocity? (km/h)

Answer 1

a) (34/60) x 66 + 130 = Z

b)  Z/((34/60) + (15/60) + 2.10) = ?

Answer 2

a.) 167.4022km

Solution: total displacement= (66 km/h)(0.5667h) + 130km= 37.4022 km + 130 km= 167.4022km

note: 34.0 mins.= 0.5667 h

b.) 57.3944 km/h

Solution: average velocity= distance/time= 167.4022km/2.9167h= 57.3944 km/h

note: 34.0 mins.+ 15 mins. + 126 mins.= 175 mins= 2.9167 h

~2.10 h=126 mins.

Answer 3

34.0 minutes at 66.0 km/h

= 34.0m × 1h/60m × 66.0 km/h

= 37.4 km.

Add to that distance the 130 km after the stop, and the total distance is 167.4 km.

The time is 34.0m + 15.0m + 2.10h * 60m/1h = 175m.

The velocity is 167.4 km / 175m * 60m/1h = 57.394 km/h.

However, those figures are more precise than the source figures, which are all three significant figures. Reducing to three significant figures, the answers are:

(a) 167. km

(b) 57.4 km/h

Answer 4

Were you driving a Ford?

Henry Ford was one of the greatest physicist ever.

Answer 5

(a) 167.4 km

(b) 57.3 km/hr

(b) is found by dividing the total distance traveled by the total time traveled.

His trip was 175 minutes long.  And his total distance was found in (a).

(a) is found by simply calculating how far he traveled in each interval and adding them together.

He traveled 37.4 km on the first stretch, none in the second interval (stopped), and a total of 130 km in the third interval.

PS. Cheers to Steve for remembering Significant Figures.

Answer 6

Question a)

(34/60) * 66 = 37.4 km on the first leg

((10/60) + 2) * 130 = 281.7 km on the second leg

Total = 37.4 + 281.7 = 319 km

Question b)

Total distance travelled (see part a) = 319 km

Total time spent: 34 min + 15 min + 2.10 h = 2.59 h

Average speed = 319 / ((0.59/60)+2) = 106.3 km/h