CBSE ADDA

CBSE SCIENCE Question: The distance (S) in metres travelled by a particle is related to time(t) in seconds by the equation of motion S = 5 t2. What is the initial velocity of the particle? nswer:   S = 0 + 5 t2 Initial velocity = 0 [because t is not 0] Question 22 Question: What conclusions do you draw about the nature of motion of the body from the following velocity-time graph? Answer: a) The object is moving with uniform acceleration (since the graph is a straight line. Straight line graph means change in velocity in equal intervals of time) b) The object is having zero acceleration (since the object is moving with uniform velocity) c) The object is moving with negative acceleration or retardation (since the velocity decreases and finally becomes zero) d) The object is moving with variable acceleration (since the change in velocity is not equal) Q uestion: State the type of motion represented by each of the following graphs: Answe

CBSE SCIENCE Question: An object covers a distance of 'S' metres in 't' seconds as follows: Plot a graph, taking 't' on X-axis and 'S' on Y axis. Answer: Q.A car travels a certain distance with a speed of 50 km/h and returns with a speed of 40 km/h. Calculate the average speed for the whole journey. Answer: Let the distance = d km  Total distance travelled by car = 2d  Total time taken    Average speed  = 44.44 km/h. Question: An artificial satellite is moving in a circular orbit of radius nearly 42,250 km. Calculate its linear velocity, if it takes 24 hour to revolve round the earth. Answer:     Linear velocity, v  = 3.07 km/s Question: The given figure shows the position of a body at different times. Calculate (i) the speed of the body as it moves for 0 to 5 s         (ii) 5 to 7 s (iii) 7 to 9 s Answer:     (i) Speed of the body as it moves from 0 to 5 s = Slope of OA  = 0.6 m s - 1 (ii) Speed from 5 to 7 s = Slope of AB