October 2020 Paper 1 Q5

OCR MEICurrent spec5 marksSUVAT Time-Series Graphs

5 A child is running up and down a path. A simplified model of the child’s motion is as follows:

he first runs north for 5 s at \(4\,\mathrm{m\,s^{-1}}\);
he then suddenly stops and waits for 8 s;
finally he runs in the opposite direction for 7 s at \(3.5\,\mathrm{m\,s^{-1}}\).

(a) Taking north to be the positive direction, sketch a velocity-time graph for this model of the child’s motion. [2]

Using this model,

(b) calculate the total distance travelled by the child, [2]

Velocity-time graph: v = 4 from t = 0 to 5, v = 0 from t = 5 to 13, v = -3.5 from t = 13 to 20 — Mark scheme (a)

Scheme	Marks	AO
	B1 B1	1.1 1.1
	[2]

Mark scheme (b)

Scheme	Marks	AO
Distance \(= (4 \times 5) + (7 \times 3.5)\) m	M1	1.1a
\(= 44.5\)	A1	1.1
	[2]

Notes

M1: finding the area of at least one region from their graph oe
May work directly from the information in the question without reference to their graph

A1: cao

Scheme	Marks	AO
Displacement \(= 20 - 24.5 = -4.5\) m	B1	1.1
	[1]