a velocity of 20 m/s. Calculate the value of kinetics
insti throw
of the body
speed of a body 15 TU m/s and its kinetic energy is 100 J. How much is the 55 of the body?
peed of car of 500 kg increased from 20 m/s to 40 m/s. How much work was done by the engine
& The specs
the speed of
of 10 m/s.
cal energy
- It begins
nergy and
I reaching
of the car?
bullet of 50 g strikes a target with a velocity of 600 m/s. Its velocity reduces to 150 m/s after peneterating
e target. How much energy of bullet was used to peneterate the target!
A bullet of 108 penetrates a target with a velocity of 100 m/s. Its velocity reduces to 60 m/s after
netrating the target. Calculate the loss in energy of the bullet in penetrating the target.
hullet of 0.10 kg is moving with a velocity of 400 ms. H.
8 moving with a velocity of 400 m/s, How much work will have to be done to stop
Law of
penetratin
12 A bullet
power of
it?
13. Calculat
14. A man takes
Tulate the work done in carrying a body of mass 10 kg to a roof of 5 m hg 8
man takes a body of 50 kg on the roof of a bus 2.5 m. Find how much work has he to do agam
avitational force? (8 = 9.8 m/s)
lass to a roof of bus 3 m high. How much work has he to do against
gravitational force? (g = 10 m/s)
aung Treely through air travels a distance of 10 m. Calculate the work done.
15. A coolie carri
(g = 10 m/s)
1 to its
rify it
1 A piece of stone of 5 kg weight is left to fall from the height of 10 m. Calculate its kinetic energy at the
time it strikes the earth. (8 = 10 m/s)
ve A body of 2 kg is lifted to a height of 4 m. How much change will take place in the potentia
the body ? (8 = 10 m/s)
19. If the potential energy of a body at earth surface is assumed as zero. How much will be the potential
energy of a body of 2 kg mass at bottom of 30 m deep well? (s = 9.8 m/s)
20. A piece of stone of 100 g weight is allowed to fall from a height of 100 m. Calculate the velocity and
kinetic energy of the stone when it reaches the earth. (g = 10 m/s)
earth
and
геrу
Hint: -mu? = mgh = v= y2gh
21. A hody of mass 2 kg falls freely, from a height of 100 m, under gravitational acceleration (3). Find its
u it roaches the earth. (g = 10 m/s)
Answers
Explanation:
Abstract
Introduction: There are many different sprint training programs such as sprint-resisted methods which have been used with the aim of improving maximal sprint running performance. In strength-specific exercises the athlete uses the sport movement with an added resistance, such as a speed chute. However, little is known about the extent to which the principle of speed specificity applies to all forms of speed chute training. This study examined the efficacy of 3 different speed chute loadings in relation to maximum running speed. Methods: A total number of 48 cadets were randomly assigned into 4 equal (n = 12) groups. The first, second and third group followed a training programme which involved 8 times a 40 m sprint using a medium, a large and 2 medium sized speed chutes respectively. The fourth group followed the same training programme entirely performing flat sprint running. The rest interval between the runs was 5 minutes and the training period lasted 7 weeks. In all cadets maximum running speed was measured via 3 maximal 40 m trials under flat and resisted conditions (groups 1, 2 and 3) pre, during (1st week) and post (8th week) the training programme, using a video camera. Results: A significantly decreased in maximum running speed was evident with the use of speed chute (pre vs. 1st week; p < 0.05) for the medium, large and 2 medium size (8.42 + 0.35 vs. 8.02 + 0.42 m/s, 8.52 + 0.35 vs. 7.92 + 0.42 m/s, and 8.52 + 0.35 vs. 7.72 + 0.42 m/s respectively). However, group 3 presented a significantly higher decline in maximum running speed compared to the other 2 sizes. Additionally, group 3 alongside with group 4 showed no significant change in maximum running speed following the 7 week training programme indicating no benefits in maximal speed phase but only in the acceleration phase via increases in step length (2.15 + 0.29 to 2.31 + 0.26 m; p < 0.05). Discussion: A medium size speed chute offers the ideal resistive load leading to improvements acceleration phase and maximal speed phase and consequently to the highest performance potentiation in sprinting compared to other loadings and the traditional flat training.