Answer:
t = 6 [s]
Explanation:
In order to solve this problem we must first use this equation of kinematics.

where:
Vf = final velocity = 0 (the car comes to rest)
Vo = initial velocity = 72 [km/h]
a = acceleration [m/s²]
x = distance = 60 [m]
First we must convert the velocity from kilometers per hour to meters per second.
![72 [\frac{km}{h}]*\frac{1000m}{1km} *\frac{1h}{3600s} =20 [m/s]](https://tex.z-dn.net/?f=72%20%5B%5Cfrac%7Bkm%7D%7Bh%7D%5D%2A%5Cfrac%7B1000m%7D%7B1km%7D%20%2A%5Cfrac%7B1h%7D%7B3600s%7D%20%3D20%20%5Bm%2Fs%5D)
![0=(20)^{2} -2*a*60\\400 = 120*a\\a=3.33[m/s^{2} ]](https://tex.z-dn.net/?f=0%3D%2820%29%5E%7B2%7D%20-2%2Aa%2A60%5C%5C400%20%3D%20120%2Aa%5C%5Ca%3D3.33%5Bm%2Fs%5E%7B2%7D%20%5D)
Now using this other equation of kinematics.

0 = 20-3.33*t
t = 6[s]
Answer:
Explanation:
Momentum conservation

Kinetic energy conservation

Solve the system
Answer:
a ut will move faster than the large object was moving initially
ZC. The forward force of the surfboard's acceleration is balanced by the backward force of the surfer's mass.
Answer:
1000 Nm
2000 Nm
1.00007 seconds
Explanation:
I = Moment of inertia = 5 kgm²
= Angular acceleration
= Final angular velocity
= Initial angular velocity
t = Time taken
Torque is given by

The torque of the disc would be 1000 Nm
If 

The torque of the disc would be 2000 Nm
From equation of rotational motion

It would take 1.00007 seconds to reach 3820 rpm