A ball is thrown horizontally from a high bridge. Compare its horizontal velocity 0.5 s and 2.0 s after it leaves the hand.
A ball leaves a balcony railing 11 m above the street at 8 m/s. Its flight lasts 1.5 s, whatever its launch speed. It lands somewhere on the street below. How far out from the balcony's base?
The horizontal distance from the launch point's base to the landing point is called the projectile's range.
While the ball falls, its horizontal velocity holds at 8 m/s from edge to landing, because once airborne no horizontal force acts on a projectile, so nothing changes its horizontal velocity.
At a steady speed, distance covered is speed multiplied by time. You have used that relation since earlier grades, and a projectile's horizontal motion is exactly a steady-speed motion.
For the balcony ball:
range = 8 × 1.5 = 12 m
The fall sets the flight time. The horizontal motion covers ground for exactly that time, and nothing else about the fall enters the multiplication.
A ball leaves a table at 3.2 m/s and is in the air for 0.5 s. Calculate its range.
Write down the values in the question:
v_x = 3.2 m/s
t = 0.5 s
range = ?
Write down the equation:
range = v_x × t
Substitute in the values:
range = 3.2 × 0.5
Simplify:
range = 1.6 m
A puck slides off a bench at 5 m/s and is in the air for 1.7 s. Enter its range in m, to one decimal place.
A stone leaves a cliff top horizontally at 15 m/s and takes 2.2 s to reach the beach. Calculate how far from the cliff's base it lands.
Write down the values in the question:
v_x = 15 m/s
t = 2.2 s
range = ?
Write down the equation:
range = v_x × t
Substitute in the values:
range = 15 × 2.2
Simplify:
range = 33.0 m
A ball rolls off a ledge at 9 m/s and lands 2.4 s later. Enter its range in m, to one decimal place.
A snowball leaves a flat roof horizontally at 7.5 m/s. It falls for 2.8 s before landing in the yard. Enter how far from the building's base it lands, in m, to one decimal place.
A marble leaves a counter at 1.5 m/s and flies for 0.6 s. Enter its range in m, to one decimal place.
A ball is kicked horizontally off a terrace at 12 m/s and takes 1.3 s to land. Enter its range in m, to one decimal place.
A ball rolls off a wall. The wall's height gives the ball a 2.0 s flight, and it leaves the wall at 6.5 m/s. Enter its range in m, to one decimal place.