Mechanics Mid Exam

Which one of the following sets of physical quantities contains only vector quantities?

• Current, energy, time, speed

• Volume, density, time, velocity

• Mass, momentum, speed, force

• Force, velocity, momentum, acceleration

Given two vectors A = 5 unit and B = 7 unit, which one of the following may not be the resultant of these vectors?

• 12 unit

• 5 unit

• 6 unit

• 35 unit

Given two vectors A = i-3j+3k and B =3i+2j+k, then what is the angle b/n the vectors?

• 90°

• 60°

• 45°

• 30°

In which type of motion, the instantaneous acceleration is equal to average acceleration?

• Uniform motion

• Uniformly accelerated motion

• In both types of motion

• undetermined

The position of a particle is given by x(t) = (2t²-4t) m, where the time t is in seconds. Which one of the following is NOT TRUE about the motion of the particle?

• Its average velocity b/n t = 1 sec and t = 4 sec is 6 m/s 

• The particle become momentarily at rest at t = 1 sec

• Its acceleration is 4 m/s²

• Its velocity at t = 2 sec is 6 m/s

Which shows the correct relation between time of flight 'T' and maximum height, H?

• H= gT^²/8

• H= 8T^²/g

• H= 8gT^²

• H= gT^²

What is the angle of projection for which the range and maximum height become equal?

• tan-1 (¼)

• tan-1 (4)

• tan-1 (½)

• tan-1 (2)

A particle starts from rest & moving with constant acceleration covers a distance x₁ in the 3^rd second and x₂ in the 5^th second. The ratio of x₁/x₂ is equal to

• 3/5

• 5/9

• 9/25

• 25/81

An object has a constant acceleration of 4m/s² at a certain instant that its velocity is 9 m/s. what is the ratio of its velocity 2 seconds later to 2 seconds earlier?

• 9:8

• 17:1

• 18:4

• 2:9

Two projectiles are fired from ground level at equal speed but different angles. One is fired at an angle of 37° and the other at 53°. The projectile to cover the longest horizontal displacement (range) will be the one fired at (neglect air resistance)?

• 53°

• 37°

• Both covers equal range

• Cannot be determined from the given information