A ball is projected from a 10 m high vertical building at an angle of 300 above

Question

A ball is projected from a 10 m high vertical building at an angle of 300 above the horizontal and hits the ground a horizontal distance of 8.77 m from the base of the building after 1.75 seconds. Assume that air resistance is negligible. QUESTION 11 Which one of the following statements about the horizontal motion of the ball is true? (f) The horizontal velocity of the ball will be 5 ms^-1. (g) The horizontal acceleration of the ball will be zero. (h) The horizontal velocity at any time during will equal the initial horizontal velocity. (j) All of these are true. QUESTION 12 The initial speed of the ball will be closest to QUESTION 13 Just at the instant before the ball strikes the ground, the magnitude of the vertical component of the velocity will be closest to

Explanation / Answer

11)

Let the initial horizontal velocitybe v

So, horizontal displacement, X = v*t = 8.77

So, v*1.75 = 8.77

So, v = 5.01 m/s

horizontal acceleration = 0 <----- no force in horizontal direction

horizontal velocity remains constant and equal to initial horizontal velocity.

So, answer is (i) all the statements are true <--------answer

12)

Now, let inital speed be V

So, V*cos30 = 5.01

So, V = 5.01/cos(30 deg) = 5.79 m/s <---------answer

13)

Using the equation of motion,

v = u + at

In vertical motion,

v = final vertical speed

u = initial vertical speed = V*sin(30 deg) = 5.79*sin(30 deg) = 2.895 m/s

a = -9.8 m/s2

t = 1.75 s

So, v = 2.895 - 9.8*1.75 = -14.26 m/s

So, magnitude = 14.26 m/s <---------answer

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.