CBSE Class 9 Answered

The velocity-time graph of a car is given below. The car weighs 1000 kg. (i) What is the distance travelled by the car in the first 2 seconds? (ii) What is the braking force at the end of 5 seconds to bring the car to a stop within one second?

Asked by Topperlearning User | 18 May, 2015, 11:19: AM

Expert Answer

$begin mathsize 12px style left parenthesis straight i right parenthesis space The space distance space travelled space by space the space car space in space first space 2 space seconds equals Area space of space ΔABE space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space equals space ½ space cross times space AE space cross times space BE space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space space equals space ½ space cross times space 2 space cross times space 15 space equals space 15 space straight m space left parenthesis ii right parenthesis space Mass space of space the space car space equals space 1000 space kg space space space space space space space space space space space space space space space space space space space space space space space space space space space straight F space equals space straight m space cross times space straight a space space space space space space Now comma space straight a space equals space slope space of space the space graph space CD space space fraction numerator 0 space minus space 15 over denominator 6 space minus space 5 end fraction equals 15 space straight m divided by straight s squared space space space Thus comma space straight F space equals space straight m space cross times space straight a space space space space space space space space space space space space space space space space space space space equals space 1000 space straight X space left parenthesis negative 15 right parenthesis space straight N space space space space space space space space space space space space space space space space space space space equals space minus 15000 space straight N space Negative space sign space indicates space that space it space is space straight a space braking space force. end style$