A ball is projected from ground level with a speed of at an angle of above the…

PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

A ball is projected from ground level with a speed of

20\,\text{m\,s}^{-1}

at an angle of

30^{\circ}

above the positive

x

-axis. Answer the following questions, taking the

x

-axis to be horizontal and the

y

-axis vertically upward. (i) Calculate the horizontal component

v_x

and the vertical component

v_y

of the initial velocity. Give each answer correct to two significant figures. (ii) Express the initial velocity vector

\mathbf{v}

in unit-vector notation with proper units. (iii) Using your results from part (i), compute the magnitude of

\mathbf{v}

again and verify that it equals the given speed of

20\,\text{m\,s}^{-1}

. Comment briefly on your result.