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2 answers:
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Answer:
(A) Distance taken by automobile to overtake truck is 175.23 m
(B) Final speed of the automobile is 29.6 m/s.
Explanation:
According to the problem, the automobile is at rest, so its initial speed is zero and the automobile is moving with constant acceleration.
The general equation of motion is:
d = ut + 0.5at² .....(1)
Here d is distance, a is acceleration, t is time and u is initial speed.
The distance (d₁) travel by the automobile after green light in time t is given by the relation :
d₁ = u₁t + 0.5at²
We know that its initial velocity is zero i.e. u = 0 m/s.
d₁ = 0.5at² ......(2)
The truck is moving with constant speed, so its acceleration is zero. Therefore, the distance covered by the truck using equation (1) is;
d₂ = u₂t .......(3)
Since, the distance travelled by automobile and truck are same. Hence,
d₁ = d₂
0.5at² = u₂t
t = 2u₂/a
Substitute 14.8 m/s for u₂ and 2.50 m/s² for a in the above equation.
t =
t = 11.84 s
(A) Distance travelled by automobile, d = u₂t =14.8 x 11.84 = 175.23 m
(B) Final speed of the automobile is given by the relation:
v = u + at
v = 0 + 2.50 x 11.84
v = 29.6 m/s
Answer:
1) 10.1 s 2) 909 m 3) 90.0 m/s 4) -99m/s 5) just over the bomb.
Explanation:
1)
- In the vertical direction, as the bomb is dropped, its initial velocity is 0.
- So, we can find the time required for the bomb to reach the earth, applying the following kinematic equation for displacement:
- where Δy = -500 m (taking the upward direction as positive).
- a=-g=-9.8 m/s²
- Replacing these values in (1), and solving for t, we have:
- The time required for the bomb to reach the earth is 10.1 s.
2)
- In the horizontal direction, once released from the helicopter, no external influence acts on the bomb, so it will continue moving forward at the same speed. that it had, equal to the helicopter.
- As the time must be the same for both movements, we can find the horizontal displacement just as the product of this speed times the time, as follows:
3)
- The horizontal component of the bomb's velocity is the same that it had when left the helicopter. i.e. 90 m/s.
4)
- In order to find the vertical component of the bomb's velocity just before it strikes the earth, we can apply the definition of acceleration, remembering that v₀ = 0, as follows:
5)
- If the helicopter keeps flying horizontally at the same speed, it will be always over the bomb, as both travel horizontally at the same speed.
- So, when the bomb hits the ground, the helicopter will be exactly over it.
Answer:
The change in momentum (in kg*m/s) = 42
Explanation:
The change in momentum is equal to
Final Momentum - Initial Momentum
As we know
Momentum is equal to the product of mass and velocity
where m is the mass of the body and v is the speed
Thus, change in momentum
here m1 = m2 = 6 Kg
Substituting the given values in above equation we get -
kg m/s