Answer:
(a) 13.43 N
(b) 1.62 m/s2
Explanation:
(a)Let g = 9.81 m/s2
The pushing force can be split into 2 components: 1 parallel and the other perpendicular to the floor:
- The parallel component:
- The perpendicular component:
Friction force is the product of coefficient and normal force, which consists of gravity and the perpendicular pushing force
(b) Horizontally speaking, the net force acting on the block is the parallel force subtracted by friction
The block acceleration according to Newton's 2nd law is
Answer: 20580 Joules of work is done by the firefighter.
Explanation:
Work done is defined as the force times distance travelled.
work=
Given:
mass= 75 kg
acceleration due to gravity =
h= height = 28 m
Putting in the values we get,
work=
Thus 20580 Joules of work is done by the firefighter.
Explanation:
Light is clearly affected by gravity, just think about a black hole, but light supposedly has no mass and gravity only affects objects with mass. On the other hand, if light does have mass then doesn't mass become infinitely larger the closer to the speed of light an object travels.
Answer:
The tension in the rod as the ball moves through the bottom circle is 9.8 N
Explanation:
When the ball is released from rest, the centripetal force equals the weight of the ball. So mv²/r = mg where m = mass of ball = 0.5 kg, v = speed of ball, r = radius of vertical circle = length of rod = 0.5 m and g = acceleration due to gravity = 9.8 m/s²
v = √gr = √9.8 m/s² × 0.5 m = √4.9 = 2.21 m/s
Now at the bottom of the circle T - mg = mv²/r where T = tension in the rod
T = m(g + v²/r)
= m(g + (√gr)²/r)
= m(g+ gr/r)
= m(g + g)
= 2mg
= 2 × 0.5 kg × 9.8 m/s²
= 9.8 N
So, the tension in the rod as the ball moves through the bottom circle is 9.8 N