Question

A truck, of mass 1250 kg, heading north crossed the median on the Jasper Highway, then slammed head-on at 25 ms into a 625 kg car heading south at 30 m s

(i) What was the initial momentum of the truck?

(ii) What was the initial momentum of the car?

Assuming the car and truck move as one following the collision, what is the speed and direction of the wreck right after the collision?​

Answer 1

Answer:

let,

m1 = 1250kg

m2 = 625kg

v1=25m/s

v2=30m/s

Initial momentum of truck = m1.v1 = 1250x25

= 31250 kgm/s

initial momentum of car = m2.v2 = 625x30

=18750 kgm/s

Answer 2

Concept:

Momentum is the quantity of motion of a moving body, measured as a product of the object's mass and velocity.

Given:

The mass of the truck is 1250kg with a velocity of $25m/s$.

The mass of the car is $625kg$ moving with a velocity of $30m/s$.

Find:

The initial momentum of truck and car.

The speed and direction of the wreck after the collision.

Solution:

The mass of the truck, $m_1=1250kg$

The velocity of the truck, $v_1=25m/s$

The mass of the car, $m_2=625kg$

The velocity of the car, $v_2=30m/s$

(i) The initial momentum of the truck is:

    $=m_1v_1\\=(1250)(25)\\=31250kg.m/s$

(ii) The initial momentum of the car is:

    $=m_2v_2\\=(625)(30)\\=18750kg.m/s$

(iii) After the collision the truck and the car move as one.

The truck was moving north and the car was moving south.

Let the momentum of the car be negative.

So, the total momentum after the collision is:

$31250-18750=12500kg.m/s$

The total combined mass is $1875kg$.

Therefore, the velocity after the collision will be:

$v=\frac{12500kg.m/s}{1875kg}$

$v=6.67m/s$

The velocity after the collision is $6.67m/s$ and the direction of the wreck will be north.

#SPJ2