91Ó°ÊÓ

Mass of the truck, m =10,000kg

Speed of the truck, v =12m/s

Mass of the SUV,$m_2=2,000\mathrm{kg}$

Kinetic energy, which may be seen in the movement of an object, particle, or group of particles, is the energy of motion.

As we know the momentum of an object is

$\stackrel{→}{p}=m\stackrel{→}{v}$

Substituting the values into the formula

$$\begin{gathered} \stackrel{→}{p}=m\stackrel{→}{v} \\ =10000kg×12m/s \\ =12×{10}^{4}kg.m/s \end{gathered}$$

Hence the magnitude of the momentum of the truck is $12×{10}^4\mathrm{kg}.\mathrm{m}/\mathrm{s}$.

$$\begin{gathered} v_2=? \\ {p}_1=12×{10}^4\mathrm{kg}.\mathrm{m}/\mathrm{s} \end{gathered}$$

According to the question, momentum is the same

$$\begin{gathered} p_1=p_1 \\ {p}_1=m_2{v}_2 \\ 12×{10}^{4}kg.m/s=2,000kg×v_2 \\ {v}_2=60m/s \end{gathered}$$

Therefore, toattainthe same momentum as the truck speed of the SUV will be 60m/s.

$m_1=10,000\mathrm{kg}$,

$$\begin{gathered} v_1=12\mathrm{m}/\mathrm{s} \\ {m}_2=2,000\mathrm{kg} \\ {v}_2=? \end{gathered}$$

According to the question, kinetic energy is the same

$$\begin{gathered} {\mathrm{K}}_1={\mathrm{K}}_2 \\ \frac{1}{2}{\mathrm{m}}_1{\mathrm{v}}_1^2=\frac{1}{2}{\mathrm{m}}_2{\mathrm{v}}_2^2 \\ \frac{1}{2}\left(10000\mathrm{kg}\right){\left(12\mathrm{m}/\mathrm{s}\right)}^2=\frac{1}{2}\left(2000\mathrm{kg}\right){\mathrm{v}}_2^2 \\ {\mathrm{v}}_2^2=\sqrt{\frac{\left(10000\mathrm{m}/\mathrm{s}\right){\left(12\mathrm{kg}\right)}^2}{2000\mathrm{kg}}} \\ {\mathrm{v}}_2=26.38\mathrm{m}/\mathrm{s} \end{gathered}$$

Therefore, to attain the same kinetic energy as the truck speed of the SUV will be 26.38m/s .