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Question

I dont get this at all. Can someone explain this to me? 

d = rt 

d =distance traveled by a moving object 
r =rate of speed 
t =time the object travels 

1. find d if r = 2.4 m/s; t = 18 s 

2. find r if d = 50 mi; t = 8.5 h 

3. find t if d = 2000 m; r = 72 m/min 

4. A skydiver is falling at a speed of 176 ft/s. How far will he fall in 2 min? 

5. The space shuttle makes an Earth orbit of 25,390 mi in 1.4 h. what is the shuttle's average speed? 

Answer 1

(1).

To find the value of d, substitute the r = 2.4 m/s, and t = 18 sec in the equation d = rt.

d = 2.4 * 18 = 43.2 meters.

 

(2).

To find the value of r, substitute the d = 50 m and t = 8.5 h  in the equation d = rt.

50 = r * 8.5

Divide each side by 8.5

50/8.5 = (r * 8.5)/8.8

50/8.5 = r

r = 5.88 m/h.

Replace 3600 s for h

r = 5.88 m/ 3600 s

r = 0.00163 m/s.

 

(3).

To find the value of t, substitute the d = 2000 m and r = 72 m/min  in the equation d = rt.

2000 = 72 * t

Divide each side by 72

2000/72 = (72 * t)/72

2000/72 = t

t = 27.78 minutes.

 

(4).

To find the value of d, substitute the r = 176 ft/s and t = 2 m = 2 * 60 s = 120 s in the equation d = rt.

d = 176 * 120 = 21120 feet.

 

(5).

To find the value of r, substitute the d = 25,390 mi and t = 1.4 h in the equation d = rt.

25390 = r * 1.4

Divide each side by 1.4

25390/1.4 = (r * 1.4)/1.4

25390/1.4 = r

r = 18135.71 mi/h.