Chapter 2, Problem 9Q

The motion of an airplane taking off on a straight runway can be described by the equation v = as +30 where s is distance in metres and a is a constant. (i) For taking off at Heathrow, the coefficient a = 0.1 per second, calculate the acceleration of the aircraft when the distance s = 400 m. (ii) If the acceleration a should be 8.5 m/s? at s = 400 m at Gatwick, calculate what the value of the coefficient a should be in order for the plane to be able to take off successfully.

Figure 2-42 shows a simple device for measuring your reaction time. It consists of a cardboard strip marked with a scale and two large dots. A friend holds the strip vertically, with thumb and forefinger at the dot on the right in Fig. 2-42. You then position your thumb and forefinger at the other dot (on the left in Fig. 2-42), being careful not to touch the strip. Your friend releases the strip, and you try to pinch it as soon as possible after you see it begin to fall. The mark at the place where you pinch the strip gives your reaction time. (a) How far from the lower dot should you place the 50.0 ms mark? How much higher should you place the marks for (b) 100, (c) 150, (d) 200, and (e) 250 ms? (For example, should the 100 ms marker be 2 times as far from the dot as the 50 ms marker? If so, give an answer of 2 times. Can you find any pattern in the answers?)

An Object is initially moving in the X direction at 5.5 m per seconds, when it undergoes an acceleration in thr Y direction for a period of 22 seconds. If the object moves equal distance in the X and Y direction During this time, what's the magnitude of its acceleration?