Answer:
4 seconds
Explanation:
Given:
v₀ = 20 m/s
v = 0 m/s
a = -5 m/s²
Find: t
v = at + v₀
0 m/s = (-5 m/s²) t + 20 m/s
t = 4 s
<u>Answer:</u>
The acceleration of the car is 
<u>Explanation:</u>
In the question it is given that car initially heads north with a velocity
. It then accelerates for
and in the end its velocity is
.
initial velocity 
time 
final velocity 
The equation of acceleration is


The value of acceleration is positive, here since the car is speeding up. If it was slowing down the value of acceleration would be negative.
Explanation:
There's not enough information in the problem to solve it. We need to know either the initial speed of the lorry, or the time it takes to stop.
For example, if we assume the initial speed of the lorry is 25 m/s, then we can find the rate of deceleration:
v² = v₀² + 2aΔx
(0 m/s)² = (25 m/s)² + 2a (50 m)
a = -6.25 m/s²
We can then use Newton's second law to find the force:
F = ma
F = (7520 kg) (-6.25 m/s²)
F = -47000 N
Answer:
F = 852 N
Explanation:
We apply Newton's second law to the trailer :
F = m*a Formula (1)
F : net force exerted by the truck on the trailer Newtons (N)
m : mass of the trailer in kilograms (kg)
a : acceleration of the trailer in meters over second square (m/s²)
Data
a=1.20 m/s² : acceleration of the trailer
m=710 kg : mass of the trailer
We replace data in the Formula (1) to calculate the net force exerted by the truck on the trailer
F = (710 kg)*(1.20 m/s²)
F = 852 N
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