



 
Mary, The expression "distance = time × rate" applies if the rate remains constant. 50 km/h = 50 km/h × 1/60 h/min × 1/60 min/sec = 50/3600 km/sec and hence maintaining a speed of 50 km/hr for 4 seconds the car will travel 50/3600 × 4 = 5/90 km. If the car is stopping its speed is decreasing and hence the distance travelled will depend on the rate at which the speed is decreasing. Harley  


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences. 