Projectile at an angle | Two-dimensional motion | Physics | Khan Academy

A projectile is launched from a rocket. What is its initial speed and the angle it is launched at from the horizontal?

• 10 m/s at 45 degrees

• 10 m/s at 30 degrees

• 20 m/s at 30 degrees

• 5 m/s at 60 degrees

To simplify the problem of finding how far the rock travels, what is the first step taken with the velocity vector?

• Multiply it by the acceleration due to gravity.

• Break it down into its vertical and horizontal components.

• Add it to the horizontal distance.

• Divide it by the time it stays in the air.

What assumption is made about air resistance when calculating how far the projectile travels?

• Air resistance increases the projectile's speed.

• Air resistance is significant and must be calculated.

• Air resistance is negligible.

• Air resistance only affects the vertical motion.

If the initial velocity of the projectile is 10 m/s at a 30-degree angle, what is the magnitude of its initial vertical velocity component? (Use sin 30° = 0.5)

• 10 m/s

• 8.66 m/s

• 5 m/s

• 2.5 m/s

An object is launched upwards with an initial vertical speed of 5 m/s. If it returns to its starting height, what is its final vertical speed?

• 0 m/s

• 5 m/s

• -5 m/s

• 10 m/s

An object is launched with an initial vertical velocity of 5 m/s upwards. When it returns to the same height, its final vertical velocity is -5 m/s. What is the change in its vertical velocity?

• 0 m/s

• -10 m/s

• 10 m/s

• -5 m/s

If the change in an object's vertical velocity is -10 m/s and the acceleration due to gravity is -9.8 m/s², how long is the object in the air? (Round to two decimal places)

• 0.98 seconds

• 1.02 seconds

• 1.96 seconds

• 2.04 seconds

An object is launched at 10 m/s at an angle of 30 degrees above the horizontal. What is the horizontal component of its initial velocity? (Use cos(30°) ≈ 0.866)

• 5 m/s

• 8.66 m/s

• 10 m/s

• 17.32 m/s