A puck of mass slides without friction on a horizontal surface

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

Problem

A puck of mass

4.0\,\text{kg}

slides without friction on a horizontal surface. At

t = 0

it is simultaneously subjected to two constant horizontal forces: •

\mathbf F_{A}

has magnitude

10\,\text N

and is directed

30^{\circ}

above the

+x

–axis. •

\mathbf F_{B}

has magnitude

8.0\,\text N

and is directed

120^{\circ}

counter-clockwise from the

+x

–axis. These are the only external forces acting on the puck in the plane for the next

2.0\,\text s

. The puck’s initial velocity is zero. (a) Resolve each force into its

x

and

y

components. Clearly indicate the sign of each component. (b) Calculate the

x

and

y

components of the net force acting on the puck. (c) Determine the

x

and

y

components of the puck’s acceleration. Then compute the magnitude of the acceleration and its direction measured counter-clockwise from the

+x

–axis. (d) Using your result from part (c), find the puck’s displacement vector after

2.0\,\text s

have elapsed.