To test the performance of its tires, a car

travels along a perfectly flat (no banking) cir-

cular track of radius 516 m. the car increases

its speed at uniform rate of

at ≡d |v|÷dt = 3.89 m/s^2

until the tires start to skid.

if the tires start to skid when the car reaches

a speed of 32.8 m/s, what is the coefficient of

static friction between the tires and the road? the acceleration of gravity is 9.8 m/s^2

Answer:

The coefficient of  static friction between the tires and the road is 1.987

Explanation:

Given:

Radius of the track, r =  516 m

Tangential Acceleration =  3.89 m/s^2

Speed,v =  32.8 m/s

To Find:

The coefficient of  static friction between the tires and the road = ?

Solution:

The radial Acceleration is given by,

Now the total acceleration is

=>

=>

=>

=>

The frictional force on the car will be f = ma------------(1)

And the force due to gravity is W = mg--------------------(2)

Now the coefficient of  static friction is

From (1) and (2)

Substituting the values, we get

answer: the correct answer is 1.

explanation: there are various process in which a radioactive nuclei decays:

1) alpha decay: in this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. the mass number is reduced by 4 units.

2) electron capture: in this decay process, a parent nuclei absorbs an electron and gets converted into a neutron. simply, a proton and an electron combines together to form a neutron. mass number does not change in this process.

3) gamma ray emission: it is a decay process in which an unstable nuclei gives excess energy by a spontaneous electromagnetic process. this decay releases . this process does not change the mass number.

4) positron emission: it is a type of decay process, in which a proton gets converted to neutron and an electron neutrino. this is also known as -decay. in this the mass number remains same.

from the above information, we see that only alpha-decay is producing a change in the mass number of the nucleus.

kepler used the data from tycho blahe (his mentor) to construct the laws of planetary motion.