Question

On a muddy football field, 110 kg line backer tackles an 85 kg half back. Immediately before collision, the line backer is slipping with a velocity of 8.8 ms^-1North and the half back is sliding with a velocity 7.2 ms^-1 east. What is the velocity at which two players move immediately after collision?

• A. 5.9 ms^-1
• B. 6.8ms^-1
• C. 8.0 ms^-1
• D. 7.6 ms^-1

Answer 1

Answer: (A)

5.9 ms^-1

Answer 2

(110 + 85)v = 110(8.8)$\widehat{j}$ + 85(7.2)$\widehat{i}$

or |$\overrightarrow{v}$| = $\frac{\sqrt{(11 \times 88)^{2} + (85 \times 7.2)^{2}}}{195} = 5.9ms^{- 1}$

tan β = $\frac{153}{242}$ or β = tan^-1$\frac{153}{242}$North of east