Question

2. A car travels 100 km with a speed of
50 km h-1 and another 200 km with a
speed of 20 km h-1. Is the motion
uniform ? Find the average speed of the
car. please solve the numericals​

Answer 1

Given :-

$\bullet\sf speed_1= 50km/h\\ \\ \bullet\sf Distance_1= 100km\\ \\ \bullet\sf Speed_2= 20km/h\\ \\ \bullet\sf Distance_2=200km$

To find :-

◆Identify the motion of car is uniform or not

◆ Average speed of car !

find the average speed

$\bigstar{\boxed{\sf Average \ speed = \dfrac{Total \ Distance }{Total \ Time }}}$

• Find the time covered by car T1

$\longrightarrow\sf Speed = \dfrac{Distance }{Time }\\ \\ \longrightarrow\sf 50=\dfrac{100}{Time}\\ \\ \longrightarrow\sf 50\times Time = 100\\ \\ \longrightarrow\sf Time = \cancel{\dfrac{100}{50}}\\ \\ \longrightarrow\sf Time_1= 2 \ hours$

Now Time 2

$\longrightarrow\sf 20= \dfrac{200}{Time}\\ \\ \longrightarrow\sf Time = \cancel{\dfrac{200}{20}}\\ \\ \longrightarrow\sf Time_2= 10 hours$

• Find the average speed

$\longrightarrow\sf Av.\ speed = \dfrac{D_1+D_2}{T_1+T_2}\\ \\ \longrightarrow\sf Av.\ speed = \dfrac{100+200}{2+10}\\ \\ \longrightarrow\sf Av.\ speed = \cancel{\dfrac{300}{12}}\\ \\ \longrightarrow\sf Av. \ speed =25km/h$

$\boxed{\textsf{\textbf{ Average \ sped \ of \ car = 25km/h}}}$

◆ The motion of car is non uniform

◆ Refer to graph