A car traveled 60 km in 2 hours,84 km in the next 1 hour, and then 68 km in 2 hours before reaching its destination. What was th
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Answer:
Explanation:
mass of car, m = 1022 kg
mass of truck, M = 1620 kg
initial velocity of truck, U = 14.5 m/s
initial velocity of car, u = 0 m/s
Let the final velocity of car is v and the final velocity of truck is V.
Collision is elastic, so the coefficient of restitution, e = 1
Use conservation of momentum
initial momentum of car + initial momentum of truck = final momentum of car + final momentum of truck
m x u + M x U = m x v + M x V
0 + 1620 x 14.5 = 1022 v + 1620 V
23490 = 1022 v + 1620 V ..... (1)
Use the formula of coefficient of restitution
1 (14.5 - 0) = v - V
14.5 = v - V
V = v - 14.5 .... (2)
Put in equation (1)
23490 = 1022 v + 1620 (v - 14.5)
23490 = 1022 v + 1620 v - 23490
46980 = 2642 v
v = 17.8 m/s
Put in equation (2)
V = 17.8 - 14.5
V = 3.3 m/s
Thus, the speed of car is 17.8 m/s and the velocity of truck is 3.3 m/s after collision.
<h2>Answer:</h2>
(a) 10N
<h2>Explanation:</h2>The sketch of the two cases has been attached to this response.
<em>Case 1: The box is pushed by a horizontal force F making it to move with constant velocity.</em>
In this case, a frictional force is opposing the movement of the box. As shown in the diagram, it can be deduced from Newton's law of motion that;
∑F = ma -------------------(i)
Where;
∑F = effective force acting on the object (box)
m = mass of the object
a = acceleration of the object
∑F = F -
m = 50kg
a = 0 [At constant velocity, acceleration is zero]
<em>Substitute these values into equation (i) as follows;</em>
F - = m x a
F - = 50 x 0
F - = 0
F = -------------------(ii)
<em>Case 2: The box is pushed by a horizontal force 1.5F making it to move with a constant velocity of 0.1m/s²</em>
In this case, the same frictional force is opposing the movement of the box.
∑F = 1.5F -
m = 50kg
a = 0.1m/s²
<em>Substitute these values into equation (i) as follows;</em>
1.5F - = m x a
1.5F - = 50 x 0.1
1.5F - = 5 ---------------------(iii)
<em>Substitute </em><em> = F from equation (ii) into equation (iii) as follows;</em>
1.5F - F = 5
0.5F = 5
F = 5 / 0.5
F = 10N
Therefore, the value of F is 10N
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