Question

a car is initially traveling at 50 km/hr. The brakes are applied and the car stops over a distance of 35m. What was the magnitude for the car's acceleration while it was breaking. ​

Answer 1

Magnitude of the acceleration is

2.75 m/s²

Given

A car is initially traveling at 50 km/hr. The brakes are applied and the car stops over a distance of 35 m

To Find

Magnitude of cars acceleration

Concept Used

We need to apply equations of kinematics

$\bf \pink{\bigstar\ \; v^2-u^2=2as}$

where ,

• v denotes final velocity
• u denotes initial velocity
• a denotes acceleration
• s denotes displacement

Solution

Given ,

• u = 50 km/h = 13.89 m/s
• v = 0 m/s

∵ Breaks are applied

• s = 35 m
• a = ? m/s²

Apply formula ,

$\bf \green{\bigstar\ \; v^2-u^2=2as}\\\\\to \rm (0)^2-(13.89)^2=2a(35)\\\\\to \rm 0-192.9=70a\\\\\to \rm 70a=-192.9\\\\\to \bf \orange{a=-2.75\ m/s^2\ \; \bigstar}$

Note : - ve sign of acceleration denotes retardation / deceleration

So , Magnitude of the acceleration is 2.75 m/s²

Answer 2

Answer:

2.75 m/s2

Explanation:

v2 = u2 - 2aS

=) u2 = 2aS (v=0)

=) 50000*50000/60*60*60*60 = 2*a*35

=) a =  50000*50000/60*60*60*60*2*35

      = 2.75 m/s2