Soru
5. In this question i and j are perpendicular horizontal unit vectors.] A particle P is moving with constant acceleration . At 2pm, the velocity of p is (3i+5j)kmh^-1 and at 2.30 pm the velocity of P is (i+7j)kmh^-1 At time T hours after 2 pm, P is moving in the direction of the vector (-i+2j) (a) Find the value of T. Another particle,Q.has velocity V_(Q) km h^-1 at time t hours after 2 pm , where v_(Q)=(-4-2t)i+(mu +3t)j and u is a constant. Given that there is an instant when the velocity of P is equal to the velocity of 9, (b) find the value of mu (6)
Çözüm
3.7
(222 Oylar)
Cenk
Usta · 5 yıl öğretmeni
Uzman doğrulaması
Cevap
To find the value of T, we need to use the concept of velocity and acceleration. Given that the particle P is moving with constant acceleration, we can find the acceleration vector by taking the difference between the final and initial velocities and dividing it by the time taken.The initial velocity at 2 pm is
and the final velocity at 2.30 pm is
. The time taken is 0.5 hours (30 minutes).So, the acceleration vector is:
Simplifying this, we get:
Now, we need to find the velocity of P at time T hours after 2 pm. We know that the velocity of P is in the direction of the vector
. Let's represent the velocity of P as
. Since the velocity is in the direction of
, we can write:
Simplifying this, we get:
Now, we can use the equation of motion to find the velocity of P at time T:
where
is the initial velocity at 2 pm, which is
.Substituting the values, we get:
Simplifying this, we get:
Now, we can solve for T by equating the coefficients of i and j on both sides of the equation:
Using the relationship
, we can substitute the values of x and y:
Simplifying this, we get:
Therefore, the value of T is
hours.To find the value of
, we need to equate the velocity of P with the velocity of Q.The velocity of P is given by:
The velocity of Q is given by:
Equating the velocities, we get:
Simplifying this, we get:
Using the relationship
, we can substitute the values of x and y:
Simplifying this, we get:
Now, we need to find the value of t when the velocities are equal. We can do this by equating the magnitudes of the velocities:
Simplifying this, we get:
Solving this equation, we get:
Substituting this value of T into the equation for
, we get:
Therefore, the value of
is
.