Answer:
a) v₃ = - 3 [m/s] The negative sign means that both vehicles will move to the left.
b) see the explanation below
Step-by-step explanation:
To solve this problem we must use the principle of conservation of linear momentum, which tells us that momentum is preserved before and after a collision.
Let's take the car's movement to the right as positive and truck movement to the left as negative, the momentum before the collision is written to the left of the equal sign, the momentum after the collision will be taken after the equal sign.
ΣMbefore = ΣMafter
M = m*v [kg*m/s]
(m₁*v₁) - (m₂*v₂) = (m₁+m₂)*v₃
where:
m₁ = mass of the car = 1500 [kg]
v₁ = velocity of the car = 5 [m/s]
m₂ = mass of the truck = 3000 [kg]
v₂ = velocity of the truck = 7 [m/s]
v₃ = final velocity [m/s]
(1500*5) - (3000*7) = (1500+3000)*v₃
v₃ = - 3 [m/s]
b)
To be able to solve the velocities we must perform the arithmetic operations of sums of velocities taking into account the sign of each one.
for the car
Vc = 5 - 3 = 2 [m/s] At the time of the crash the car experiences a speed reduction of 2 [ m/s]
for the truck
Vt = 7 - 3 = 4 [m/s] At the time of the crash the truck experiences a speed reduction of 4 [ m/s]