If a wave hits a smooth surface at an angle of incidence of 40 degrees, the angle of reflection is

Angle of reflection will be

Explanation:

We have given angle of incidence from the smooth surface is

So angle of incidence =

We have to find the angle of reflection

From l;aw of reflection we know that angle of reflection is equal to the angle of incidence

So angle of reflection will be equal to

b. lifting dumbbell weight at 20-degree angle from the body after a 45-degree angle

  distance on the y-axis and time on the x-axis.

explanation:

the instantaneous velocity = change in position/time taken

the slope of the graph should give instantaneous velocity.

  slope of a graph = change in value of y -axis / change in values of x -axis

  comparing both the equations

    change in value of y -axis = change in position

  change in values of x -axis = time taken

so position values should be on the y axis and time values should be on the x axis.

distance on the y-axis and time on the x-axis.