Question

Q1.
(a) A car accelerates at a constant rate of 1.83 m/s? along a flat straight road.
The force acting on the car is 1.870 KN.
Calculate the mass of the car.
Give your answer to three significant figures.
mass =

(b)
The car accelerates from rest for 16s.
Calculate the speed of the car after 16s.
speed=

(c)
The car starts on another journey. Figure 6 shows the graph of the car’s movement. (Figure at top)
Show that the distance travelled when the car is moving at a constant speed is greater than the distance travelled when the car is slowing down.

Answer 1

a) force = mass • acceleration
Convert: 1.870 KN -> 1870 N
1870N = mass • 1.83 m/s^2
———- —————-
1.83 m/s^2. 1.83 m/s^2
-> approx. 1,021.9 grams :D

b) Vi = Vf - at
0 m/s = Vf - 1.83 m/s^2 • 16s
0m/s = Vf - 29.28
+29.28 + 29.28
Vf = 29.28 m/s :D

c) x = Vi + 1/2 • at^2
A to B
T= 15s
Vi = 16m / s
A = 1.83m/s^2
x= 16 + 1/2 • 1.83(15)^2)
x = approx. 221. 9 meters

C to D
T = 9s
Vi= 30m/s
x = 30 + 1/2 1.83(9)^2
x= approx. 104.1 meters

Therefore, when the car is moving at a CONSTANT RATE, it’s traveling farther than when slowing down cause it travel 221.9 meters while slowing down, it’s going only 104.1 meters.