As we know that reaction time will be
so the distance moved by car in reaction time
now the distance remain after that from intersection point is given by
So our distance from the intersection will be 100 m when we apply brakes
now this distance should be covered till the car will stop
so here we will have
now from kinematics equation we will have
so the acceleration required by brakes is -2 m/s/s
Now total time taken to stop the car after applying brakes will be given as
total time to stop the car is given as
A roller coaster accelerates from an initial velocity of 6.0 m/s to a final velocity of 70 m/s over 4 seconds. whats the acceleration
Answer:
Explanation:
First of all, we need to find the pressure exerted on the sphere, which is given by:
where
is the atmospheric pressure
is the water density
is the gravitational acceleration
is the depth
Substituting,
The radius of the sphere is r = d/2= 1.1 m/2= 0.55 m
So the total area of the sphere is
And so, the inward force exerted on it is
k = spring constant of the spring = 85 N/m
m = mass of the box sliding towards the spring = 3.5 kg
v = speed of box just before colliding with the spring = ?
x = compression the spring = 6.5 cm = 6.5 cm (1 m /100 cm) = 0.065 m
the kinetic energy of box just before colliding with the spring converts into the spring energy of the spring when it is fully compressed.
Using conservation of energy
Kinetic energy of spring before collision = spring energy of spring after compression
(0.5) m v² = (0.5) k x²
m v² = k x²
inserting the values
(3.5 kg) v² = (85 N/m) (0.065 m)²
v = 0.32 m/s
To make the motor turn faster we can:
(a) increase the current
(b) use stronger magnets
(c) push the magnets closer to the coil
(d) put an iron centre piece into the coil
(e) adding more sets of coils
